diff --git a/packages/testing/src/execution_testing/cli/pytest_commands/plugins/consume/simulators/single_test_client.py b/packages/testing/src/execution_testing/cli/pytest_commands/plugins/consume/simulators/single_test_client.py
index 4045f92221..00670b28fe 100644
--- a/packages/testing/src/execution_testing/cli/pytest_commands/plugins/consume/simulators/single_test_client.py
+++ b/packages/testing/src/execution_testing/cli/pytest_commands/plugins/consume/simulators/single_test_client.py
@@ -33,6 +33,9 @@ def client_genesis(fixture: BlockchainFixtureCommon) -> dict:
     alloc = to_json(fixture.pre)
     # NOTE: nethermind requires account keys without '0x' prefix
     genesis["alloc"] = {k.replace("0x", ""): v for k, v in alloc.items()}
+    # NOTE: geth expects slotNumber as plain integer, not hex string
+    if "slotNumber" in genesis:
+        genesis["slotNumber"] = int(genesis["slotNumber"], 16)
     return genesis
 
 
diff --git a/packages/testing/src/execution_testing/fixtures/blockchain.py b/packages/testing/src/execution_testing/fixtures/blockchain.py
index 23145e6238..02c4c53f36 100644
--- a/packages/testing/src/execution_testing/fixtures/blockchain.py
+++ b/packages/testing/src/execution_testing/fixtures/blockchain.py
@@ -210,6 +210,10 @@ class FixtureHeader(CamelModel):
     block_access_list_hash: (
         Annotated[Hash, HeaderForkRequirement("bal_hash")] | None
     ) = Field(None, alias="blockAccessListHash")
+    slot_number: (
+        Annotated[ZeroPaddedHexNumber, HeaderForkRequirement("slot_number")]
+        | None
+    ) = Field(None)
 
     fork: Fork | None = Field(None, exclude=True)
 
@@ -361,7 +365,7 @@ def get_default_from_annotation(
     def genesis(cls, fork: Fork, env: Environment, state_root: Hash) -> Self:
         """Get the genesis header for the given fork."""
         environment_values = env.model_dump(
-            exclude_none=True, exclude={"withdrawals"}
+            exclude_none=True, exclude={"withdrawals", "slot_number"}
         )
         if env.withdrawals is not None:
             environment_values["withdrawals_root"] = Withdrawal.list_root(
@@ -378,6 +382,11 @@ def genesis(cls, fork: Fork, env: Environment, state_root: Hash) -> Self:
                 if fork.header_bal_hash_required(block_number=0, timestamp=0)
                 else None
             ),
+            "slot_number": (
+                0
+                if fork.header_slot_number_required(block_number=0, timestamp=0)
+                else None
+            ),
             "fork": fork,
         }
         return cls(**environment_values, **extras)
@@ -418,6 +427,7 @@ class FixtureExecutionPayload(CamelModel):
     block_access_list: Bytes | None = Field(
         None, description="RLP-serialized EIP-7928 Block Access List"
     )
+    slot_number: HexNumber | None = Field(None)
 
     @classmethod
     def from_fixture_header(
diff --git a/packages/testing/src/execution_testing/forks/base_fork.py b/packages/testing/src/execution_testing/forks/base_fork.py
index 89fa18afc2..f36fd557ab 100644
--- a/packages/testing/src/execution_testing/forks/base_fork.py
+++ b/packages/testing/src/execution_testing/forks/base_fork.py
@@ -361,6 +361,14 @@ def header_bal_hash_required(
         """Return true if the header must contain block access list hash."""
         pass
 
+    @classmethod
+    @abstractmethod
+    def header_slot_number_required(
+        cls, *, block_number: int = 0, timestamp: int = 0
+    ) -> bool:
+        """Return true if the header must contain slot number (EIP-7843)."""
+        pass
+
     # Gas related abstract methods
 
     @classmethod
diff --git a/packages/testing/src/execution_testing/forks/forks/forks.py b/packages/testing/src/execution_testing/forks/forks/forks.py
index c2deb27bae..72624785d2 100644
--- a/packages/testing/src/execution_testing/forks/forks/forks.py
+++ b/packages/testing/src/execution_testing/forks/forks/forks.py
@@ -976,6 +976,14 @@ def header_beacon_root_required(
         del block_number, timestamp
         return False
 
+    @classmethod
+    def header_slot_number_required(
+        cls, *, block_number: int = 0, timestamp: int = 0
+    ) -> bool:
+        """At genesis, header must not contain slot number (EIP-7843)."""
+        del block_number, timestamp
+        return False
+
     @classmethod
     def engine_new_payload_blob_hashes(
         cls, *, block_number: int = 0, timestamp: int = 0
@@ -3338,9 +3346,7 @@ class Amsterdam(BPO2):
     def header_bal_hash_required(
         cls, *, block_number: int = 0, timestamp: int = 0
     ) -> bool:
-        """
-        From Amsterdam, header must contain block access list hash (EIP-7928).
-        """
+        """BAL hash in header required from Amsterdam (EIP-7928)."""
         del block_number, timestamp
         return True
 
@@ -3367,3 +3373,36 @@ def engine_execution_payload_block_access_list(
         """
         del block_number, timestamp
         return True
+
+    @classmethod
+    def header_slot_number_required(
+        cls, *, block_number: int = 0, timestamp: int = 0
+    ) -> bool:
+        """Slot number in header required from Amsterdam (EIP-7843)."""
+        del block_number, timestamp
+        return True
+
+    @classmethod
+    def opcode_gas_map(
+        cls, *, block_number: int = 0, timestamp: int = 0
+    ) -> Dict[OpcodeBase, int | Callable[[OpcodeBase], int]]:
+        """Add SLOTNUM opcode gas cost for Amsterdam (EIP-7843)."""
+        gas_costs = cls.gas_costs(
+            block_number=block_number, timestamp=timestamp
+        )
+        base_map = super(Amsterdam, cls).opcode_gas_map(
+            block_number=block_number, timestamp=timestamp
+        )
+        return {
+            **base_map,
+            Opcodes.SLOTNUM: gas_costs.G_BASE,
+        }
+
+    @classmethod
+    def valid_opcodes(
+        cls, *, block_number: int = 0, timestamp: int = 0
+    ) -> List[Opcodes]:
+        """Add SLOTNUM opcode for Amsterdam (EIP-7843)."""
+        return [Opcodes.SLOTNUM] + super(Amsterdam, cls).valid_opcodes(
+            block_number=block_number, timestamp=timestamp
+        )
diff --git a/packages/testing/src/execution_testing/specs/blockchain.py b/packages/testing/src/execution_testing/specs/blockchain.py
index b5a6ddffe9..fdd5dd1d2c 100644
--- a/packages/testing/src/execution_testing/specs/blockchain.py
+++ b/packages/testing/src/execution_testing/specs/blockchain.py
@@ -154,6 +154,7 @@ class Header(CamelModel):
     parent_beacon_block_root: Removable | Hash | None = None
     requests_hash: Removable | Hash | None = None
     bal_hash: Removable | Hash | None = None
+    slot_number: Removable | HexNumber | None = None
 
     REMOVE_FIELD: ClassVar[Removable] = Removable()
     """
@@ -325,6 +326,8 @@ def set_environment(self, env: Environment) -> Environment:
             and self.block_access_list is not None
         ):
             new_env_values["block_access_list"] = self.block_access_list
+        if not isinstance(self.slot_number, Removable):
+            new_env_values["slot_number"] = self.slot_number
         """
         These values are required, but they depend on the previous environment,
         so they can be calculated here.
@@ -651,6 +654,12 @@ def generate_block_data(
             fork=self.fork,
         )
 
+        # Clear block_access_list_hash if the fork doesn't require it
+        if not self.fork.header_bal_hash_required(
+            block_number=int(env.number), timestamp=int(env.timestamp)
+        ):
+            header.block_access_list_hash = None
+
         if block.header_verify is not None:
             # Verify the header after transition tool processing.
             try:
@@ -747,8 +756,10 @@ def generate_block_data(
             bal = block.expected_block_access_list.modify_if_invalid_test(
                 t8n_bal
             )
-            if bal != t8n_bal:
-                # If the BAL was modified, update the header hash
+            if bal != t8n_bal and self.fork.header_bal_hash_required(
+                block_number=int(env.number), timestamp=int(env.timestamp)
+            ):
+                # If the BAL was modified and the fork requires it, update the header hash
                 header.block_access_list_hash = Hash(bal.rlp.keccak256())
 
         built_block = BuiltBlock(
diff --git a/packages/testing/src/execution_testing/specs/state.py b/packages/testing/src/execution_testing/specs/state.py
index e4d5f9c61c..1e1869e33f 100644
--- a/packages/testing/src/execution_testing/specs/state.py
+++ b/packages/testing/src/execution_testing/specs/state.py
@@ -310,6 +310,7 @@ def _generate_blockchain_blocks(self) -> List[Block]:
             "extra_data": self.env.extra_data,
             "withdrawals": self.env.withdrawals,
             "parent_beacon_block_root": self.env.parent_beacon_block_root,
+            "slot_number": self.env.slot_number,
             "txs": [self.tx],
             "ommers": [],
             "header_verify": self.blockchain_test_header_verify,
diff --git a/packages/testing/src/execution_testing/specs/static_state/environment.py b/packages/testing/src/execution_testing/specs/static_state/environment.py
index 32cd3b4e6d..89b42cbe45 100644
--- a/packages/testing/src/execution_testing/specs/static_state/environment.py
+++ b/packages/testing/src/execution_testing/specs/static_state/environment.py
@@ -33,6 +33,7 @@ class EnvironmentInStateTestFiller(BaseModel):
     current_excess_blob_gas: ValueInFiller | None = Field(
         None, alias="currentExcessBlobGas"
     )
+    current_slot_number: ValueInFiller | None = Field(None, alias="slotNumber")
 
     model_config = ConfigDict(extra="forbid")
 
@@ -72,4 +73,6 @@ def get_environment(self, tags: TagDict) -> Environment:
             kwargs["base_fee_per_gas"] = self.current_base_fee
         if self.current_excess_blob_gas is not None:
             kwargs["excess_blob_gas"] = self.current_excess_blob_gas
+        if self.current_slot_number is not None:
+            kwargs["slot_number"] = self.current_slot_number
         return Environment(**kwargs)
diff --git a/packages/testing/src/execution_testing/test_types/block_types.py b/packages/testing/src/execution_testing/test_types/block_types.py
index 2c73a558b9..26bcb4ea03 100644
--- a/packages/testing/src/execution_testing/test_types/block_types.py
+++ b/packages/testing/src/execution_testing/test_types/block_types.py
@@ -101,6 +101,7 @@ class EnvironmentGeneric(CamelModel, Generic[NumberBoundTypeVar]):
     excess_blob_gas: NumberBoundTypeVar | None = Field(
         None, alias="currentExcessBlobGas"
     )
+    slot_number: NumberBoundTypeVar | None = Field(None, alias="slotNumber")
 
     parent_difficulty: NumberBoundTypeVar | None = Field(None)
     parent_timestamp: NumberBoundTypeVar | None = Field(None)
@@ -223,6 +224,14 @@ def set_fork_requirements(self, fork: Fork) -> "Environment":
         ):
             updated_values["parent_beacon_block_root"] = 0
 
+        if (
+            fork.header_slot_number_required(
+                block_number=number, timestamp=timestamp
+            )
+            and self.slot_number is None
+        ):
+            updated_values["slot_number"] = 0
+
         return self.copy(**updated_values)
 
     def __hash__(self) -> int:
diff --git a/packages/testing/src/execution_testing/vm/opcodes.py b/packages/testing/src/execution_testing/vm/opcodes.py
index 31f7cf10e9..aaf52a9501 100644
--- a/packages/testing/src/execution_testing/vm/opcodes.py
+++ b/packages/testing/src/execution_testing/vm/opcodes.py
@@ -2225,6 +2225,36 @@ class Opcodes(Opcode, Enum):
     Source: [EIP-7516](https://eips.ethereum.org/EIPS/eip-7516)
     """
 
+    SLOTNUM = Opcode(0x4B, popped_stack_items=0, pushed_stack_items=1)
+    """
+    SLOTNUM() = slotNumber
+    ----
+
+    Description
+    ----
+    Returns the current slot number as provided by the consensus layer.
+    The slot number is passed from the consensus layer to the execution
+    layer through the engine API.
+
+    Inputs
+    ----
+    - None
+
+    Outputs
+    ----
+    - slotNumber: current slot number (uint64)
+
+    Fork
+    ----
+    TBD
+
+    Gas
+    ----
+    2
+
+    Source: [EIP-7843](https://eips.ethereum.org/EIPS/eip-7843)
+    """
+
     POP = Opcode(0x50, popped_stack_items=1)
     """
     POP()
diff --git a/src/ethereum/forks/amsterdam/blocks.py b/src/ethereum/forks/amsterdam/blocks.py
index ef44549d28..df28972b47 100644
--- a/src/ethereum/forks/amsterdam/blocks.py
+++ b/src/ethereum/forks/amsterdam/blocks.py
@@ -253,6 +253,13 @@ class Header:
     [EIP-7928]: https://eips.ethereum.org/EIPS/eip-7928
     [cbalh]: ref:ethereum.forks.amsterdam.block_access_lists.rlp_utils.compute_block_access_list_hash
     """  # noqa: E501
+    slot_number: U64
+    """
+    The slot number of this block as provided by the consensus layer.
+    Introduced in [EIP-7843].
+
+    [EIP-7843]: https://eips.ethereum.org/EIPS/eip-7843
+    """
 
 
 @slotted_freezable
diff --git a/src/ethereum/forks/amsterdam/fork.py b/src/ethereum/forks/amsterdam/fork.py
index 3e45c3e953..3bde867199 100644
--- a/src/ethereum/forks/amsterdam/fork.py
+++ b/src/ethereum/forks/amsterdam/fork.py
@@ -249,6 +249,7 @@ def state_transition(chain: BlockChain, block: Block) -> None:
         excess_blob_gas=block.header.excess_blob_gas,
         parent_beacon_block_root=block.header.parent_beacon_block_root,
         state_changes=StateChanges(),
+        slot_number=block.header.slot_number,
     )
 
     block_output = apply_body(
diff --git a/src/ethereum/forks/amsterdam/vm/__init__.py b/src/ethereum/forks/amsterdam/vm/__init__.py
index 3d69fbd706..d6596ee5d6 100644
--- a/src/ethereum/forks/amsterdam/vm/__init__.py
+++ b/src/ethereum/forks/amsterdam/vm/__init__.py
@@ -50,6 +50,7 @@ class BlockEnvironment:
     excess_blob_gas: U64
     parent_beacon_block_root: Hash32
     state_changes: StateChanges
+    slot_number: U64
 
 
 @dataclass
diff --git a/src/ethereum/forks/amsterdam/vm/instructions/__init__.py b/src/ethereum/forks/amsterdam/vm/instructions/__init__.py
index 0da72c8ea5..d858b5053f 100644
--- a/src/ethereum/forks/amsterdam/vm/instructions/__init__.py
+++ b/src/ethereum/forks/amsterdam/vm/instructions/__init__.py
@@ -99,6 +99,7 @@ class Ops(enum.Enum):
     BASEFEE = 0x48
     BLOBHASH = 0x49
     BLOBBASEFEE = 0x4A
+    SLOTNUM = 0x4B
 
     # Control Flow Ops
     STOP = 0x00
@@ -251,6 +252,7 @@ class Ops(enum.Enum):
     Ops.PREVRANDAO: block_instructions.prev_randao,
     Ops.GASLIMIT: block_instructions.gas_limit,
     Ops.CHAINID: block_instructions.chain_id,
+    Ops.SLOTNUM: block_instructions.slot_number,
     Ops.MLOAD: memory_instructions.mload,
     Ops.MSTORE: memory_instructions.mstore,
     Ops.MSTORE8: memory_instructions.mstore8,
diff --git a/src/ethereum/forks/amsterdam/vm/instructions/block.py b/src/ethereum/forks/amsterdam/vm/instructions/block.py
index e563a2e96e..2ca11e7462 100644
--- a/src/ethereum/forks/amsterdam/vm/instructions/block.py
+++ b/src/ethereum/forks/amsterdam/vm/instructions/block.py
@@ -259,3 +259,36 @@ def chain_id(evm: Evm) -> None:
 
     # PROGRAM COUNTER
     evm.pc += Uint(1)
+
+
+def slot_number(evm: Evm) -> None:
+    """
+    Push the current slot number onto the stack.
+
+    The slot number is provided by the consensus layer and passed to the
+    execution layer through the engine API.
+
+    Parameters
+    ----------
+    evm :
+        The current EVM frame.
+
+    Raises
+    ------
+    :py:class:`~ethereum.forks.amsterdam.vm.exceptions.StackOverflowError`
+        If `len(stack)` is equal to `1024`.
+    :py:class:`~ethereum.forks.amsterdam.vm.exceptions.OutOfGasError`
+        If `evm.gas_left` is less than `2`.
+
+    """
+    # STACK
+    pass
+
+    # GAS
+    charge_gas(evm, GAS_BASE)
+
+    # OPERATION
+    push(evm.stack, U256(evm.message.block_env.slot_number))
+
+    # PROGRAM COUNTER
+    evm.pc += Uint(1)
diff --git a/src/ethereum_spec_tools/evm_tools/loaders/fork_loader.py b/src/ethereum_spec_tools/evm_tools/loaders/fork_loader.py
index 9a14efa54c..8204e12ea3 100644
--- a/src/ethereum_spec_tools/evm_tools/loaders/fork_loader.py
+++ b/src/ethereum_spec_tools/evm_tools/loaders/fork_loader.py
@@ -268,6 +268,15 @@ def has_withdrawal(self) -> bool:
         """Check if the fork has a `Withdrawal` class."""
         return hasattr(self._module("blocks"), "Withdrawal")
 
+    @property
+    def has_slot_number(self) -> bool:
+        """Check if the fork supports the SLOTNUM opcode (EIP-7843)."""
+        try:
+            block_env = self._module("vm").BlockEnvironment
+            return "slot_number" in block_env.__dataclass_fields__
+        except (ModuleNotFoundError, AttributeError):
+            return False
+
     @property
     def decode_transaction(self) -> Any:
         """decode_transaction function of the fork."""
diff --git a/src/ethereum_spec_tools/evm_tools/t8n/__init__.py b/src/ethereum_spec_tools/evm_tools/t8n/__init__.py
index 4988ef25bc..258f812c8b 100644
--- a/src/ethereum_spec_tools/evm_tools/t8n/__init__.py
+++ b/src/ethereum_spec_tools/evm_tools/t8n/__init__.py
@@ -311,6 +311,8 @@ def block_environment(self) -> Any:
 
         if self.fork.has_block_access_list_hash:
             kw_arguments["state_changes"] = StateChanges()
+        if self.fork.has_slot_number:
+            kw_arguments["slot_number"] = self.env.slot_number
 
         return block_environment(**kw_arguments)
 
diff --git a/src/ethereum_spec_tools/evm_tools/t8n/env.py b/src/ethereum_spec_tools/evm_tools/t8n/env.py
index be719ba7af..c68cb4fd7f 100644
--- a/src/ethereum_spec_tools/evm_tools/t8n/env.py
+++ b/src/ethereum_spec_tools/evm_tools/t8n/env.py
@@ -53,6 +53,7 @@ class Env:
     parent_excess_blob_gas: Optional[U64]
     parent_blob_gas_used: Optional[U64]
     excess_blob_gas: Optional[U64]
+    slot_number: Optional[U64]
     requests: Any
 
     def __init__(self, t8n: "T8N", stdin: Optional[Dict] = None):
@@ -86,6 +87,8 @@ def __init__(self, t8n: "T8N", stdin: Optional[Dict] = None):
                 )
             self.read_excess_blob_gas(data, t8n)
 
+        self.read_slot_number(data, t8n)
+
     def read_excess_blob_gas(self, data: Any, t8n: "T8N") -> None:
         """
         Read the excess_blob_gas from the data. If the excess blob gas is
@@ -147,6 +150,8 @@ def read_excess_blob_gas(self, data: Any, t8n: "T8N") -> None:
 
         if t8n.fork.has_block_access_list_hash:
             arguments["block_access_list_hash"] = Hash32(b"\0" * 32)
+        if t8n.fork.has_slot_number:
+            arguments["slot_number"] = U64(0)
 
         parent_header = t8n.fork.Header(**arguments)
 
@@ -222,6 +227,16 @@ def read_randao(self, data: Any, t8n: "T8N") -> None:
                 left_pad_zero_bytes(hex_to_bytes(current_random), 32)
             )
 
+    def read_slot_number(self, data: Any, t8n: "T8N") -> None:
+        """
+        Read the slot number from the data.
+        The slot number is provided by the consensus layer.
+        """
+        self.slot_number = None
+        if t8n.fork.has_slot_number:
+            if "slotNumber" in data:
+                self.slot_number = parse_hex_or_int(data["slotNumber"], U64)
+
     def read_withdrawals(self, data: Any, t8n: "T8N") -> None:
         """
         Read the withdrawals from the data.
diff --git a/tests/amsterdam/eip7843_slotnum/__init__.py b/tests/amsterdam/eip7843_slotnum/__init__.py
new file mode 100644
index 0000000000..540001d5d9
--- /dev/null
+++ b/tests/amsterdam/eip7843_slotnum/__init__.py
@@ -0,0 +1 @@
+"""Tests for [EIP-7843: SLOTNUM](https://eips.ethereum.org/EIPS/eip-7843)."""
diff --git a/tests/amsterdam/eip7843_slotnum/spec.py b/tests/amsterdam/eip7843_slotnum/spec.py
new file mode 100644
index 0000000000..3896ea8ae1
--- /dev/null
+++ b/tests/amsterdam/eip7843_slotnum/spec.py
@@ -0,0 +1,22 @@
+"""Reference spec for [EIP-7843: SLOTNUM](https://eips.ethereum.org/EIPS/eip-7843)."""
+
+from dataclasses import dataclass
+
+
+@dataclass(frozen=True)
+class ReferenceSpec:
+    """Reference specification."""
+
+    git_path: str
+    version: str
+
+
+ref_spec_7843 = ReferenceSpec(
+    git_path="EIPS/eip-7843.md",
+    version="8140e7f3a1c93249e9e9ee5ab5281396341306ec",
+)
+
+
+@dataclass(frozen=True)
+class Spec:
+    """Constants and parameters from EIP-7843."""
diff --git a/tests/amsterdam/eip7843_slotnum/test_slotnum.py b/tests/amsterdam/eip7843_slotnum/test_slotnum.py
new file mode 100644
index 0000000000..1e18cf536a
--- /dev/null
+++ b/tests/amsterdam/eip7843_slotnum/test_slotnum.py
@@ -0,0 +1,112 @@
+"""Tests for EIP-7843 (SLOTNUM)."""
+
+import pytest
+from execution_testing import (
+    Account,
+    Alloc,
+    Environment,
+    Fork,
+    Op,
+    StateTestFiller,
+    Transaction,
+)
+
+from .spec import ref_spec_7843
+
+REFERENCE_SPEC_GIT_PATH = ref_spec_7843.git_path
+REFERENCE_SPEC_VERSION = ref_spec_7843.version
+
+pytestmark = pytest.mark.valid_from("Amsterdam")
+
+
+@pytest.mark.parametrize(
+    "slot_number",
+    [
+        pytest.param(0, id="slot_zero"),
+        pytest.param(1, id="slot_one"),
+        pytest.param(0x1000, id="slot_4096"),
+        pytest.param(2**32, id="slot_large"),
+        pytest.param(2**64 - 1, id="slot_max_u64"),
+    ],
+)
+def test_slotnum_value(
+    state_test: StateTestFiller,
+    pre: Alloc,
+    slot_number: int,
+) -> None:
+    """
+    Test that SLOTNUM opcode returns the correct slot number.
+
+    The slot number is provided by the consensus layer and should be
+    accessible via the SLOTNUM opcode (0x4B).
+    """
+    # Store SLOTNUM result at storage key 0
+    code = Op.SSTORE(0, Op.SLOTNUM)
+    code_address = pre.deploy_contract(code)
+
+    tx = Transaction(
+        sender=pre.fund_eoa(),
+        gas_limit=100_000,
+        to=code_address,
+    )
+
+    post = {
+        code_address: Account(
+            storage={0: slot_number},
+        ),
+    }
+
+    state_test(
+        env=Environment(slot_number=slot_number),
+        pre=pre,
+        tx=tx,
+        post=post,
+    )
+
+
+@pytest.mark.parametrize(
+    "gas_delta,call_succeeds",
+    [
+        pytest.param(0, True, id="enough_gas"),
+        pytest.param(-1, False, id="out_of_gas"),
+    ],
+)
+def test_slotnum_gas_cost(
+    state_test: StateTestFiller,
+    pre: Alloc,
+    fork: Fork,
+    gas_delta: int,
+    call_succeeds: bool,
+) -> None:
+    """
+    Test that SLOTNUM opcode costs exactly 2 gas (G_BASE).
+    """
+    slotnum_gas = Op.SLOTNUM.gas_cost(fork)
+    call_gas = slotnum_gas + gas_delta
+
+    # Callee just executes SLOTNUM
+    callee_code = Op.SLOTNUM + Op.STOP
+    callee_address = pre.deterministic_deploy_contract(deploy_code=callee_code)
+
+    # Caller calls the callee with limited gas and stores result
+    caller_code = Op.SSTORE(0, Op.CALL(gas=call_gas, address=callee_address))
+    caller_address = pre.deploy_contract(caller_code)
+
+    tx = Transaction(
+        sender=pre.fund_eoa(),
+        gas_limit=100_000,
+        to=caller_address,
+    )
+
+    post = {
+        caller_address: Account(
+            storage={0: 1 if call_succeeds else 0},
+        ),
+    }
+
+    state_test(
+        env=Environment(slot_number=12345),
+        pre=pre,
+        tx=tx,
+        post=post,
+    )
diff --git a/whitelist.txt b/whitelist.txt
index 2cf28a9928..ac4aabc52b 100644
--- a/whitelist.txt
+++ b/whitelist.txt
@@ -1099,6 +1099,7 @@ SignerType
 signextend
 simlimit
 sload
+SLOTNUM
 slt
 smod
 socketserver