diff --git a/core/block_validator.go b/core/block_validator.go
index 82460b804b57..1bd7cf7f4798 100644
--- a/core/block_validator.go
+++ b/core/block_validator.go
@@ -56,6 +56,10 @@ func NewBlockValidator(config *params.ChainConfig, blockchain *BlockChain, engin
 // header's transaction and uncle roots. The headers are assumed to be already
 // validated at this point.
 func (v *BlockValidator) ValidateBody(block *types.Block) error {
+	// check EIP-7934 RLP-encoded block size cap
+	if v.config.IsOsaka(block.Number()) && block.Size() > params.MaxBlockSize {
+		return ErrBlockOversized
+	}
 	// Check whether the block's known, and if not, that it's linkable
 	if v.bc.HasBlockAndFullState(block.Hash(), block.NumberU64()) {
 		return ErrKnownBlock
diff --git a/core/block_validator_test.go b/core/block_validator_test.go
index d3f498826dc9..b53f60152059 100644
--- a/core/block_validator_test.go
+++ b/core/block_validator_test.go
@@ -17,6 +17,7 @@
 package core
 
 import (
+	"math/big"
 	"testing"
 	"time"
 
@@ -25,6 +26,7 @@ import (
 	"github.com/XinFinOrg/XDPoSChain/core/types"
 	"github.com/XinFinOrg/XDPoSChain/core/vm"
 	"github.com/XinFinOrg/XDPoSChain/params"
+	"github.com/XinFinOrg/XDPoSChain/trie"
 )
 
 // Tests that simple header verification works, for both good and bad blocks.
@@ -76,3 +78,46 @@ func TestHeaderVerification(t *testing.T) {
 		chain.InsertChain(blocks[i : i+1])
 	}
 }
+
+func TestValidateBodyBlockOversizedOsakaByBlockNumber(t *testing.T) {
+	testdb := rawdb.NewMemoryDatabase()
+	cfg := *params.TestChainConfig
+	cfg.OsakaBlock = big.NewInt(2)
+	gspec := &Genesis{Config: &cfg}
+	genesis := gspec.MustCommit(testdb)
+
+	chain, err := NewBlockChain(testdb, nil, gspec, ethash.NewFaker(), vm.Config{})
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer chain.Stop()
+
+	validator := NewBlockValidator(&cfg, chain, ethash.NewFaker())
+	oversizedData := make([]byte, params.MaxBlockSize+1024)
+	tx := types.NewTx(&types.LegacyTx{
+		Nonce:    0,
+		Gas:      params.TxGas,
+		GasPrice: big.NewInt(1),
+		Data:     oversizedData,
+	})
+
+	newOversizedBlock := func(number uint64, ts uint64) *types.Block {
+		header := &types.Header{
+			ParentHash: genesis.Hash(),
+			Number:     new(big.Int).SetUint64(number),
+			Time:       ts,
+			GasLimit:   30_000_000,
+		}
+		return types.NewBlock(header, &types.Body{Transactions: []*types.Transaction{tx}}, nil, trie.NewStackTrie(nil))
+	}
+
+	preOsaka := newOversizedBlock(1, ^uint64(0))
+	if err := validator.ValidateBody(preOsaka); err == ErrBlockOversized {
+		t.Fatalf("pre-Osaka block should not trigger ErrBlockOversized")
+	}
+
+	postOsaka := newOversizedBlock(2, 0)
+	if err := validator.ValidateBody(postOsaka); err != ErrBlockOversized {
+		t.Fatalf("post-Osaka oversized block mismatch: have %v, want %v", err, ErrBlockOversized)
+	}
+}
diff --git a/core/error.go b/core/error.go
index 227da000072d..87bde0c6bd79 100644
--- a/core/error.go
+++ b/core/error.go
@@ -31,6 +31,10 @@ var (
 
 	// ErrNoGenesis is returned when there is no Genesis Block.
 	ErrNoGenesis = errors.New("genesis not found in chain")
+
+	// ErrBlockOversized is returned if the size of the RLP-encoded block
+	// exceeds the cap established by EIP-7934
+	ErrBlockOversized = errors.New("block RLP-encoded size exceeds maximum")
 )
 
 // List of evm-call-message pre-checking errors. All state transtion messages will
diff --git a/miner/worker.go b/miner/worker.go
index a7dfca72f12e..2ed32a7332b2 100644
--- a/miner/worker.go
+++ b/miner/worker.go
@@ -62,6 +62,10 @@ const (
 	chainSideChanSize = 10
 
 	txMatchGasLimit = 40000000
+
+	// Block size is capped by the protocol at params.MaxBlockSize. During
+	// production keep a safety margin for auxiliary fields added to the block.
+	maxBlockSizeBufferZone = 1_000_000
 )
 
 var (
@@ -90,6 +94,7 @@ type Work struct {
 	signer types.Signer
 	state  *state.StateDB // apply state changes here
 	tcount int            // tx count in cycle
+	size   uint64         // size of the block we are building
 	evm    *vm.EVM
 
 	parentState  *state.StateDB
@@ -108,6 +113,15 @@ type Work struct {
 	createdAt time.Time
 }
 
+// txFitsSize reports whether the transaction fits into the block size limit.
+func (w *Work) txFitsSize(tx *types.Transaction) bool {
+	// this Osaka-specific cap is not enforced pre-fork
+	if w.config.IsOsaka(w.header.Number) {
+		return w.size+tx.Size() < params.MaxBlockSize-maxBlockSizeBufferZone
+	}
+	return true
+}
+
 type Result struct {
 	Work  *Work
 	Block *types.Block
@@ -712,6 +726,7 @@ func (w *worker) makeCurrent(parent *types.Block, header *types.Header) error {
 		config:       w.chainConfig,
 		signer:       types.MakeSigner(w.chainConfig, header.Number),
 		state:        state,
+		size:         uint64(header.Size()),
 		parentState:  state.Copy(),
 		tradingState: XDCxState,
 		lendingState: lendingState,
@@ -1080,6 +1095,10 @@ func (w *Work) commitTransactions(mux *event.TypeMux, balanceFee map[common.Addr
 	var coalescedLogs []*types.Log
 	// first priority for special Txs
 	for _, tx := range specialTxs {
+		if !w.txFitsSize(tx) {
+			log.Debug("Skipping oversized transaction", "hash", tx.Hash(), "size", tx.Size())
+			continue
+		}
 		to := tx.To()
 		if w.header.Number.Uint64() >= common.DenylistHFNumber {
 			from := tx.From()
@@ -1193,6 +1212,12 @@ func (w *Work) commitTransactions(mux *event.TypeMux, balanceFee map[common.Addr
 			break
 		}
 		tx := resolvedTx
+		// if inclusion of the transaction would put the block size over the
+		// maximum we allow, don't add any more txs to the payload.
+		if !w.txFitsSize(tx) {
+			log.Debug("Skipping oversized transaction", "hash", tx.Hash(), "size", tx.Size())
+			break
+		}
 		to := tx.To()
 		if w.header.Number.Uint64() >= common.DenylistHFNumber {
 			from := tx.From()
@@ -1330,6 +1355,7 @@ func (w *Work) commitTransaction(balanceFee map[common.Address]*big.Int, tx *typ
 	}
 	w.txs = append(w.txs, tx)
 	w.receipts = append(w.receipts, receipt)
+	w.size += tx.Size()
 
 	return receipt.Logs, tokenFeeUsed, gas, nil
 }
diff --git a/params/protocol_params.go b/params/protocol_params.go
index 99f79d58fc26..7e72ae8c470a 100644
--- a/params/protocol_params.go
+++ b/params/protocol_params.go
@@ -170,6 +170,8 @@ const (
 	Bn256PairingPerPointGasIstanbul  uint64 = 34000  // Per-point price for an elliptic curve pairing check
 
 	HistoryServeWindow = 8191 // Number of blocks to serve historical block hashes for, EIP-2935.
+
+	MaxBlockSize uint64 = 8_388_608 // maximum size of an RLP-encoded block
 )
 
 var (