diff --git a/dix/pixmap.c b/dix/pixmap.c
index 6923e7e7bf219b98b56632d73bc3353f81a3fd98..061bd421de6e003a503f06628c76232e99175c25 100644
--- a/dix/pixmap.c
+++ b/dix/pixmap.c
@@ -117,7 +117,7 @@ AllocatePixmap(ScreenPtr pScreen, int pixDataSize)
     if (pScreen->totalPixmapSize > ((size_t) - 1) - pixDataSize)
         return NullPixmap;
 
-    pPixmap = malloc(pScreen->totalPixmapSize + pixDataSize);
+    pPixmap = calloc(1, pScreen->totalPixmapSize + pixDataSize);
     if (!pPixmap)
         return NullPixmap;