diff --git a/tests/v1/engine/test_llm_engine.py b/tests/v1/engine/test_llm_engine.py
index 7e5196efc873..65dbb0e48199 100644
--- a/tests/v1/engine/test_llm_engine.py
+++ b/tests/v1/engine/test_llm_engine.py
@@ -79,10 +79,11 @@ def _get_test_sampling_params(
     structured_outputs: bool = False,
 ) -> tuple[list[SamplingParams], list[int]]:
     """Generate random sampling params for a batch."""
+    rng = random.Random(seed)
 
     def get_mostly_n_gt1() -> int:
         r"""Mostly n \in [2,20], ~1/3 n=1"""
-        x = random.randint(0, 28)
+        x = rng.randint(0, 28)
         if x < 10:
             return 1
         else: