diff --git a/blosc/blosc-private.h b/blosc/blosc-private.h
index 06e6c6e2..64097f07 100644
--- a/blosc/blosc-private.h
+++ b/blosc/blosc-private.h
@@ -184,7 +184,9 @@ extern int g_ntuners;
 
 #if defined(_WIN32)
 #include <windows.h>
+#ifndef PATH_MAX
 #define PATH_MAX MAX_PATH
+#endif
 #define RTLD_LAZY   0x000
 #define popen _popen
 #define pclose _pclose