diff --git a/mingw-w64-crt/misc/mingw-fseek.c b/mingw-w64-crt/misc/mingw-fseek.c
index 506ffda..3a0c41e 100644
--- a/mingw-w64-crt/misc/mingw-fseek.c
+++ b/mingw-w64-crt/misc/mingw-fseek.c
@@ -56,7 +56,7 @@
       printf ("__mingw_fwrite: current %I64u, actual %I64u\n", 
 	      current_position.QuadPart, actual_length.QuadPart);
 #endif /* DEBUG */
-      if (current_position.QuadPart > actual_length.QuadPart)
+      if ((size_t)current_position.QuadPart > (size_t)actual_length.QuadPart)
 	{
 	  static char __mingw_zeros[ZEROBLOCKSIZE];
 	  long long numleft;