diff --git a/vllm/utils/deep_gemm.py b/vllm/utils/deep_gemm.py
index 56326c9315ba..8b5713e02c95 100644
--- a/vllm/utils/deep_gemm.py
+++ b/vllm/utils/deep_gemm.py
@@ -99,7 +99,7 @@ def fp8_m_grouped_gemm_nt_masked(*args, **kwargs):
 
 def per_block_cast_to_fp8(x, *args, **kwargs):
     if _per_block_cast_impl is not None and is_blackwell_deep_gemm_used():
-        return _per_block_cast_impl(x)
+        return _per_block_cast_impl(x, use_ue8m0=True)
     # TODO: refactor the `per_block_cast_to_fp8` from tests to vllm utils
     from tests.kernels.quant_utils import per_block_cast_to_fp8 as _pbcf
     return _pbcf(x, *args, **kwargs)