diff --git a/wp-blog-header.php b/wp-blog-header.php
index 3f98ede1ac..117b9c1f64 100644
--- a/wp-blog-header.php
+++ b/wp-blog-header.php
@@ -114,10 +114,13 @@ if (is_404()) {
 	@header ('X-Pingback: '. get_bloginfo('pingback_url'));
 } else {
 	// We're showing a feed, so WP is indeed the only thing that last changed
-	$wp_last_modified = mysql2date('D, d M Y H:i:s', get_lastpostmodified('GMT'), 0).' GMT';
+	if ( $withcomments )
+		$wp_last_modified = mysql2date('D, d M Y H:i:s', get_lastcommentmodified('GMT'), 0).' GMT';
+	else 
+		$wp_last_modified = mysql2date('D, d M Y H:i:s', get_lastpostmodified('GMT'), 0).' GMT';
 	$wp_etag = '"' . md5($wp_last_modified) . '"';
-	@header('Last-Modified: '.$wp_last_modified);
-	@header('ETag: '.$wp_etag);
+	@header("Last-Modified: $wp_last_modified");
+	@header("ETag: $wp_etag");
 	@header ('X-Pingback: ' . get_bloginfo('pingback_url'));
 
 	// Support for Conditional GET
diff --git a/wp-commentsrss2.php b/wp-commentsrss2.php
index f8ed8f3245..0dc406286f 100644
--- a/wp-commentsrss2.php
+++ b/wp-commentsrss2.php
@@ -1,5 +1,6 @@
 <?php 
-if (! $feed) {
+if ( !$feed ) {
+	$withcomments = 1;
     require('wp-blog-header.php');
 }
 
diff --git a/wp-includes/functions.php b/wp-includes/functions.php
index e36ba2a26d..952ae73143 100644
--- a/wp-includes/functions.php
+++ b/wp-includes/functions.php
@@ -141,6 +141,30 @@ function get_lastpostmodified($timezone = 'server') {
 	return $lastpostmodified;
 }
 
+function get_lastcommentmodified($timezone = 'server') {
+	global $tablecomments, $cache_lastcommentmodified, $pagenow, $wpdb;
+	$add_seconds_blog = get_settings('gmt_offset') * 3600;
+	$add_seconds_server = date('Z');
+	$now = current_time('mysql', 1);
+	if ( !isset($cache_lastcommentmodified[$timezone]) ) {
+		switch(strtolower($timezone)) {
+			case 'gmt':
+				$lastcommentmodified = $wpdb->get_var("SELECT comment_date_gmt FROM $tablecomments WHERE comment_date_gmt <= '$now' ORDER BY comment_date_gmt DESC LIMIT 1");
+				break;
+			case 'blog':
+				$lastcommentmodified = $wpdb->get_var("SELECT comment_date FROM $tablecomments WHERE comment_date_gmt <= '$now' ORDER BY comment_date_gmt DESC LIMIT 1");
+				break;
+			case 'server':
+				$lastcommentmodified = $wpdb->get_var("SELECT DATE_ADD(comment_date_gmt, INTERVAL '$add_seconds_server' SECOND) FROM $tablecomments WHERE comment_date_gmt <= '$now' ORDER BY comment_date_gmt DESC LIMIT 1");
+				break;
+		}
+		$cache_lastcommentmodified[$timezone] = $lastcommentmodified;
+	} else {
+		$lastcommentmodified = $cache_lastcommentmodified[$timezone];
+	}
+	return $lastcommentmodified;
+}
+
 function user_pass_ok($user_login,$user_pass) {
 	global $cache_userdata;
 	if ( empty($cache_userdata[$user_login]) ) {