diff --git a/system/helpers/url_helper.php b/system/helpers/url_helper.php
index 14c216a..36ff0ff 100644
--- a/system/helpers/url_helper.php
+++ b/system/helpers/url_helper.php
@@ -152,7 +152,7 @@
 
 		if ( ! is_array($uri))
 		{
-			$site_url = preg_match('!^\w+://! i', $uri) ? $uri : site_url($uri);
+			$site_url = preg_match('#^(\w+:)?//#i', $uri) ? $uri : site_url($uri);
 		}
 		else
 		{
@@ -191,7 +191,7 @@
 	function anchor_popup($uri = '', $title = '', $attributes = FALSE)
 	{
 		$title = (string) $title;
-		$site_url = preg_match('!^\w+://! i', $uri) ? $uri : site_url($uri);
+		$site_url = preg_match('#^(\w+:)?//#i', $uri) ? $uri : site_url($uri);
 
 		if ($title === '')
 		{
@@ -535,7 +535,7 @@
 	 */
 	function redirect($uri = '', $method = 'auto', $code = NULL)
 	{
-		if ( ! preg_match('#^https?://#i', $uri))
+		if ( ! preg_match('#^(\w+:)?//#i', $uri))
 		{
 			$uri = site_url($uri);
 		}
diff --git a/user_guide_src/source/changelog.rst b/user_guide_src/source/changelog.rst
index 5cecffe..daf7965 100644
--- a/user_guide_src/source/changelog.rst
+++ b/user_guide_src/source/changelog.rst
@@ -73,6 +73,7 @@
 	 - Added JS window name support to the :php:func:`anchor_popup()` function.
 	 - Added support (auto-detection) for HTTP/1.1 response code 303 in :php:func:`redirect()`.
 	 - Changed :php:func:`redirect()` to only choose the **refresh** method only on IIS servers, instead of all servers on Windows (when **auto** is used).
+	 - Changed :php:func:`anchor()`, :php:func:`anchor_popup()`, and :php:func:`redirect()` to support protocol-relative URLs, such as `redirect('//ellislab.com/codeigniter')`.
    -  Added XHTML Basic 1.1 doctype to :doc:`HTML Helper <helpers/html_helper>`.
    -  :doc:`Inflector Helper <helpers/inflector_helper>` changes include:
 	 - Changed :php:func:`humanize()` to allow passing an input separator as its second parameter.