diff --git a/ChangeLog b/ChangeLog
index 7a226449e..a1048b619 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+2017-07-07 Riccardo Mottola <rm@gnu.org>
+
+	* Source/NSProcessInfo.m:
+	Fix GetTickCount()/GetTickCount64() for different Windows versions.
+
 2017-07-04  Richard Frith-Macdonald <rfm@gnu.org>
 
 	* Source/NSObject.m: When an object's retain count is incremented too
diff --git a/Source/NSProcessInfo.m b/Source/NSProcessInfo.m
index b4c4df2fc..da94da15c 100644
--- a/Source/NSProcessInfo.m
+++ b/Source/NSProcessInfo.m
@@ -1,5 +1,5 @@
 /** Implementation for NSProcessInfo for GNUStep
-   Copyright (C) 1995-2014 Free Software Foundation, Inc.
+   Copyright (C) 1995-2017 Free Software Foundation, Inc.
 
    Written by:  Georg Tuparev <Tuparev@EMBL-Heidelberg.de>
                 Heidelberg, Germany
@@ -1470,7 +1470,13 @@ static void determineOperatingSystem()
   NSUInteger uptime = 0;
 
 #if	defined(_WIN32)
+
+#if _WIN32_WINNT < 0x0600 /* less than Vista */
+  uptime = GetTickCount() / 1000;
+#else
   uptime = GetTickCount64() / 1000;
+#endif
+  
 #elif	defined(HAVE_SYSCTLBYNAME)
   struct timeval	tval;
   size_t		len = sizeof(tval);