diff --git a/reactos/drivers/net/ndis/ndis/control.c b/reactos/drivers/net/ndis/ndis/control.c
index c7cd3102dd7..ec2db26170b 100644
--- a/reactos/drivers/net/ndis/ndis/control.c
+++ b/reactos/drivers/net/ndis/ndis/control.c
@@ -50,7 +50,7 @@ NdisAcquireReadWriteLock(
 {
   ULONG RefCount;
   UCHAR ProcessorNumber;
-  UCHAR BusyLoop;
+  volatile UCHAR BusyLoop;
 
   ASSERT_IRQL(DISPATCH_LEVEL);