diff --git a/Libraries/LibC/inttypes.h b/Libraries/LibC/inttypes.h
index fb6b932765..41e6df4c66 100644
--- a/Libraries/LibC/inttypes.h
+++ b/Libraries/LibC/inttypes.h
@@ -26,3 +26,4 @@
 
 #define PRIdPTR __PRIPTR_PREFIX "d"
 #define PRIiPTR __PRIPTR_PREFIX "i"
+#define PRIXPTR __PRIPTR_PREFIX "X"