diff --git a/src/Valitron/Validator.php b/src/Valitron/Validator.php
index b456b52..c5947ae 100644
--- a/src/Valitron/Validator.php
+++ b/src/Valitron/Validator.php
@@ -725,7 +725,7 @@ class Validator
             } else {
                 $cardRegex = array(
                     'visa'          => '#^4[0-9]{12}(?:[0-9]{3})?$#',
-                    'mastercard'    => '#^5[1-5][0-9]{14}$#',
+                    'mastercard'    => '#^(5[1-5]|2[2-7])[0-9]{14}$#',
                     'amex'          => '#^3[47][0-9]{13}$#',
                     'dinersclub'    => '#^3(?:0[0-5]|[68][0-9])[0-9]{11}$#',
                     'discover'      => '#^6(?:011|5[0-9]{2})[0-9]{12}$#',
diff --git a/tests/Valitron/ValidateTest.php b/tests/Valitron/ValidateTest.php
index 459e5c1..ceb10bb 100644
--- a/tests/Valitron/ValidateTest.php
+++ b/tests/Valitron/ValidateTest.php
@@ -994,7 +994,7 @@ class ValidateTest extends BaseTestCase
     public function testCreditCardValid()
     {
         $visa         = array(4539511619543489, 4532949059629052, 4024007171194938, 4929646403373269, 4539135861690622);
-        $mastercard   = array(5162057048081965, 5382687859049349, 5484388880142230, 5464941521226434, 5473481232685965);
+        $mastercard   = array(5162057048081965, 5382687859049349, 5484388880142230, 5464941521226434, 5473481232685965, 2223000048400011, 2223520043560014);
         $amex         = array(371442067262027, 340743030537918, 345509167493596, 343665795576848, 346087552944316);
         $dinersclub   = array(30363194756249, 30160097740704, 38186521192206, 38977384214552, 38563220301454);
         $discover     = array(6011712400392605, 6011536340491809, 6011785775263015, 6011984124619056, 6011320958064251);