diff --git a/libguile/coop-defs.h b/libguile/coop-defs.h
index 13f826d3b..918713b51 100644
--- a/libguile/coop-defs.h
+++ b/libguile/coop-defs.h
@@ -49,7 +49,7 @@
 #include "libguile/__scm.h"
 #include "libguile/iselect.h"
 
-#ifdef SCM_HAVE_WINSOCK2_H
+#if SCM_HAVE_WINSOCK2_H
 # include <winsock2.h>
 #endif