diff --git a/onnxruntime/core/mlas/lib/cast.cpp b/onnxruntime/core/mlas/lib/cast.cpp
index a6138e29bd..9b5800b08e 100644
--- a/onnxruntime/core/mlas/lib/cast.cpp
+++ b/onnxruntime/core/mlas/lib/cast.cpp
@@ -15,11 +15,6 @@ Abstract:
 --*/
 #include "mlasi.h"
 
-union fp32_bits {
-    uint32_t u;
-    float f;
-};
-
 void
 MLASCALL
 MlasConvertHalfToFloatBuffer(