diff --git a/ChangeLog b/ChangeLog
index 124ae3aafd..8db2e27a6e 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+Fri Jun  6 16:44:37 2008  NAKAMURA Usaku  <usa@ruby-lang.org>
+
+	* win32/win32.h: include ws2tcpip.h. fixed [ruby-Bugs-20528]
+
 Fri Jun  6 12:20:33 2008  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* ext/iconv/iconv.c (iconv_iconv): fixed backport miss.
diff --git a/win32/win32.h b/win32/win32.h
index 524ad7431f..b6ebab04ae 100644
--- a/win32/win32.h
+++ b/win32/win32.h
@@ -25,6 +25,7 @@
 #endif
 #ifdef USE_WINSOCK2
 #include <winsock2.h>
+#include <ws2tcpip.h>
 #include <windows.h>
 #else
 #include <windows.h>