diff --git a/Mesh/meshGRegionBoundaryRecovery.cpp b/Mesh/meshGRegionBoundaryRecovery.cpp
index 78f1595fb6e3593088b4aee7832290d79be6f84b..26d1eda8dc6bc08bf546f0e8cbf1b98e3b7f0f6a 100644
--- a/Mesh/meshGRegionBoundaryRecovery.cpp
+++ b/Mesh/meshGRegionBoundaryRecovery.cpp
@@ -21,8 +21,12 @@
 #if !defined(HAVE_NO_STDINT_H)
 #include <stdint.h>
 #elif defined(HAVE_NO_INTPTR_T)
+#if defined(_WIN64)
+typedef unsigned __int64 uintptr_t;
+#else
 typedef unsigned long uintptr_t;
 #endif
+#endif
 
 namespace tetgenBR
 {