diff --git a/wp-includes/functions.php b/wp-includes/functions.php
index 6502446175..48ed2326ac 100644
--- a/wp-includes/functions.php
+++ b/wp-includes/functions.php
@@ -525,7 +525,7 @@ function trackback($trackback_url, $title, $excerpt, $ID) {
 	$url = urlencode(get_permalink($ID));
 	$query_string = "title=$title&url=$url&blog_name=$blog_name&excerpt=$excerpt";
 	$trackback_url = parse_url($trackback_url);
-	$http_request  = 'POST ' . $trackback_url['path'] . $trackback_url['query'] . " HTTP/1.0\r\n";
+	$http_request  = 'POST ' . $trackback_url['path'] . ($trackback_url['query'] ? '?'.$trackback_url['query'] : '') . " HTTP/1.0\r\n";
 	$http_request .= 'Host: '.$trackback_url['host']."\r\n";
 	$http_request .= 'Content-Type: application/x-www-form-urlencoded; charset='.get_settings('blog_charset')."\r\n";
 	$http_request .= 'Content-Length: '.strlen($query_string)."\r\n";