diff --git a/sys/sys/_types.h b/sys/sys/_types.h
index ffef9d8b9abc..7904a4f77898 100644
--- a/sys/sys/_types.h
+++ b/sys/sys/_types.h
@@ -35,7 +35,7 @@
 /*
  * Standard type definitions.
  */
-typedef	__uint32_t	__blksize_t;	/* file block size */
+typedef	__int32_t	__blksize_t;	/* file block size */
 typedef	__int64_t	__blkcnt_t;	/* file block count */
 typedef	__int32_t	__clockid_t;	/* clock_gettime()... */
 typedef	__uint32_t	__fflags_t;	/* file flags */