diff --git a/ChangeLog b/ChangeLog
index aa89caf350..80194ce195 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Thu Sep 30 10:55:38 2010  NAKAMURA Usaku  <usa@ruby-lang.org>
+
+	* hash.c (ruby_setenv): workaround for old Windows. a patch from
+	  Heesob Park. [ruby-core:32353]
+
 Thu Sep 30 09:29:06 2010  NARUSE, Yui  <naruse@ruby-lang.org>
 
 	* lib/uri/common.rb (URI.encode_www_form): change treatment of
diff --git a/hash.c b/hash.c
index 73f90125f9..3e1731d5a3 100644
--- a/hash.c
+++ b/hash.c
@@ -2158,7 +2158,8 @@ ruby_setenv(const char *name, const char *value)
     rb_str_resize(buf, 0);
     if (!value || !*value) {
 	/* putenv() doesn't handle empty value */
-	if (!SetEnvironmentVariable(name,value)) goto fail;
+	if (!SetEnvironmentVariable(name, value) &&
+	    GetLastError() != ERROR_ENVVAR_NOT_FOUND) goto fail;
     }
     if (failed) goto fail;
 #elif defined(HAVE_SETENV) && defined(HAVE_UNSETENV)