diff --git a/src/glx/x11/glxcmds.c b/src/glx/x11/glxcmds.c
index 2efe191..f5522d9 100644
--- a/src/glx/x11/glxcmds.c
+++ b/src/glx/x11/glxcmds.c
@@ -1395,7 +1395,8 @@ glXChooseVisual(Display * dpy, int screen, int *attribList)
                                   &visualTemplate, &i);
 
          if (newList) {
-            Xfree(visualList);
+            if (visualList)
+               XFree(visualList);
             visualList = newList;
             best_config = modes;
          }