diff --git a/python/sglang/srt/managers/tokenizer_manager.py b/python/sglang/srt/managers/tokenizer_manager.py
index 81f36faa616..38a8fa53af7 100644
--- a/python/sglang/srt/managers/tokenizer_manager.py
+++ b/python/sglang/srt/managers/tokenizer_manager.py
@@ -604,7 +604,7 @@ def _create_tokenized_object(
             sampling_kwargs = obj.sampling_params
         sampling_params = SamplingParams(**sampling_kwargs)
         sampling_params.normalize(self.tokenizer)
-        sampling_params.verify()
+        sampling_params.verify(self.model_config.vocab_size)
 
         # Build return object
         if isinstance(obj, GenerateReqInput):
diff --git a/python/sglang/srt/sampling/sampling_params.py b/python/sglang/srt/sampling/sampling_params.py
index e0a88107fff..b7d1a6d6e2c 100644
--- a/python/sglang/srt/sampling/sampling_params.py
+++ b/python/sglang/srt/sampling/sampling_params.py
@@ -89,7 +89,7 @@ def __init__(
         if self.top_k == -1:
             self.top_k = TOP_K_ALL  # whole vocabulary
 
-    def verify(self):
+    def verify(self, vocab_size):
         if self.temperature < 0.0:
             raise ValueError(
                 f"temperature must be non-negative, got {self.temperature}."
@@ -131,6 +131,13 @@ def verify(self):
                     f"min_new_tokens must be in [0, max_new_tokens({self.max_new_tokens})], got "
                     f"{self.min_new_tokens}."
                 )
+        if self.logit_bias is not None:
+            for token_id in self.logit_bias:
+                if not 0 <= int(token_id) < vocab_size:
+                    raise ValueError(
+                        f"logit_bias must has keys in [0, {vocab_size - 1}], got "
+                        f"{token_id}."
+                    )
         grammars = [
             self.json_schema,
             self.regex,