diff --git a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/zfs_debug.h b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/zfs_debug.h
index 708b60004a2..43d037d7b07 100644
--- a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/zfs_debug.h
+++ b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/zfs_debug.h
@@ -43,8 +43,10 @@ extern "C" {
  */
 
 #if defined(DEBUG) || !defined(_KERNEL)
+#if !defined(ZFS_DEBUG)
 #define	ZFS_DEBUG
 #endif
+#endif
 
 extern int zfs_flags;