diff --git a/vllm/v1/worker/gpu_input_batch.py b/vllm/v1/worker/gpu_input_batch.py
index c0e9ff0286d..d5ed615ab23 100644
--- a/vllm/v1/worker/gpu_input_batch.py
+++ b/vllm/v1/worker/gpu_input_batch.py
@@ -264,9 +264,12 @@ def add_request(
         self.top_p_cpu[req_index] = sampling_params.top_p
         if sampling_params.top_p < 1:
             self.top_p_reqs.add(req_id)
-        self.top_k_cpu[req_index] = sampling_params.top_k
-        if sampling_params.top_k > 0:
+        top_k = sampling_params.top_k
+        if 0 < top_k < self.vocab_size:
             self.top_k_reqs.add(req_id)
+        else:
+            top_k = self.vocab_size
+        self.top_k_cpu[req_index] = top_k
         self.min_p_cpu[req_index] = sampling_params.min_p
         self.frequency_penalties_cpu[
             req_index] = sampling_params.frequency_penalty