diff --git a/cpukit/zlib/zconf.h b/cpukit/zlib/zconf.h
index 55319ef348..ea939082ab 100644
--- a/cpukit/zlib/zconf.h
+++ b/cpukit/zlib/zconf.h
@@ -255,11 +255,20 @@
 #  define FAR
 #endif
 
+#if defined(__rtems__)
+#include <rtems/stdint.h>
+
+typedef uint_least8_t 	Byte;
+typedef uint_least16_t	uInt;
+typedef uint_least32_t	uLong;
+
+#else
 #if !defined(__MACTYPES__)
 typedef unsigned char  Byte;  /* 8 bits */
 #endif
 typedef unsigned int   uInt;  /* 16 bits or more */
 typedef unsigned long  uLong; /* 32 bits or more */
+#endif
 
 #ifdef SMALL_MEDIUM
    /* Borland C/C++ and some old MSC versions ignore FAR inside typedef */