diff -u a/include/opus_defines.h b/include/opus_defines.h
--- a/include/opus_defines.h
+++ b/include/opus_defines.h
@@ -64,7 +64,7 @@ extern "C" {
 /**Export control for opus functions */
 
 #ifndef OPUS_EXPORT
-# if defined(WIN32)
+# if defined(_WIN32)
 #  if defined(OPUS_BUILD) && defined(DLL_EXPORT)
 #   define OPUS_EXPORT __declspec(dllexport)
 #  else
diff -u a/silk/debug.c b/silk/debug.c
--- a/silk/debug.c
+++ b/silk/debug.c
@@ -65,7 +65,7 @@
 int           silk_Timer_nTimers = 0;
 int           silk_Timer_depth_ctr = 0;
 char          silk_Timer_tags[silk_NUM_TIMERS_MAX][silk_NUM_TIMERS_MAX_TAG_LEN];
-#ifdef WIN32
+#ifdef _WIN32
 LARGE_INTEGER silk_Timer_start[silk_NUM_TIMERS_MAX];
 #else
 unsigned long silk_Timer_start[silk_NUM_TIMERS_MAX];
@@ -76,7 +76,7 @@
 opus_int64     silk_Timer_max[silk_NUM_TIMERS_MAX];
 opus_int64     silk_Timer_depth[silk_NUM_TIMERS_MAX];
 
-#ifdef WIN32
+#ifdef _WIN32
 void silk_TimerSave(char *file_name)
 {
     if( silk_Timer_nTimers > 0 )