diff --git a/modules/filter/filter.module b/modules/filter/filter.module
index f4bab9e..324c1f2 100644
--- a/modules/filter/filter.module
+++ b/modules/filter/filter.module
@@ -1484,7 +1484,7 @@ function _filter_url($text, $filter) {
   $tasks['_filter_url_parse_full_links'] = $pattern;
 
   // Match e-mail addresses.
-  $url_pattern = "[A-Za-z0-9._-]{1,254}@(?:$domain)";
+  $url_pattern = "[A-Za-z0-9._+-]{1,254}@(?:$domain)";
   $pattern = "`($url_pattern)`";
   $tasks['_filter_url_parse_email_links'] = $pattern;
 
diff --git a/modules/filter/filter.test b/modules/filter/filter.test
index ddea6af..0706333 100644
--- a/modules/filter/filter.test
+++ b/modules/filter/filter.test
@@ -1273,6 +1273,7 @@ class FilterUnitTestCase extends DrupalUnitTestCase {
     // Create a e-mail that is too long.
     $long_email = str_repeat('a', 254) . '@example.com';
     $too_long_email = str_repeat('b', 255) . '@example.com';
+    $email_with_plus_sign = 'one+two@example.com';
 
 
     // Filter selection/pattern matching.
@@ -1286,12 +1287,13 @@ http://example.com or www.example.com
       ),
       // MAILTO URLs.
       '
-person@example.com or mailto:person2@example.com or ' . $long_email . ' but not ' . $too_long_email . '
+person@example.com or mailto:person2@example.com or ' . $email_with_plus_sign . ' or ' . $long_email . ' but not ' . $too_long_email . '
 ' => array(
         '<a href="mailto:person@example.com">person@example.com</a>' => TRUE,
         '<a href="mailto:person2@example.com">mailto:person2@example.com</a>' => TRUE,
         '<a href="mailto:' . $long_email . '">' . $long_email . '</a>' => TRUE,
         '<a href="mailto:' . $too_long_email . '">' . $too_long_email . '</a>' => FALSE,
+        '<a href="mailto:' . $email_with_plus_sign . '">' . $email_with_plus_sign . '</a>' => TRUE,
       ),
       // URI parts and special characters.
       '