diff --git app/code/core/Mage/Payment/Model/Method/Cc.php app/code/core/Mage/Payment/Model/Method/Cc.php
index 4ee5bcd..a429744 100644
--- app/code/core/Mage/Payment/Model/Method/Cc.php
+++ app/code/core/Mage/Payment/Model/Method/Cc.php
@@ -105,6 +105,10 @@ class Mage_Payment_Model_Method_Cc extends Mage_Payment_Model_Method_Abstract
                 || ($this->OtherCcType($info->getCcType()) && $this->validateCcNumOther($ccNumber))) {
 
                 $ccType = 'OT';
+                $discoverNetworkRegexp = '/^(30[0-5]\d{13}|3095\d{12}|35(2[8-9]\d{12}|[3-8]\d{13})|36\d{12}'
+                    . '|3[8-9]\d{14}|6011(0\d{11}|[2-4]\d{11}|74\d{10}|7[7-9]\d{10}|8[6-9]\d{10}|9\d{11})'
+                    . '|62(2(12[6-9]\d{10}|1[3-9]\d{11}|[2-8]\d{12}|9[0-1]\d{11}|92[0-5]\d{10})|[4-6]\d{13}'
+                    . '|8[2-8]\d{12})|6(4[4-9]\d{13}|5\d{14}))$/';
                 $ccTypeRegExpList = array(
                     //Solo, Switch or Maestro. International safe
                     /*
@@ -115,21 +119,25 @@ class Mage_Payment_Model_Method_Cc extends Mage_Payment_Model_Method_Abstract
                     */
                     // Solo only
                     'SO' => '/(^(6334)[5-9](\d{11}$|\d{13,14}$))|(^(6767)(\d{12}$|\d{14,15}$))/',
-                    'SM' => '/(^(5[0678])\d{11,18}$)|(^(6[^05])\d{11,18}$)|(^(601)[^1]\d{9,16}$)|(^(6011)\d{9,11}$)'
-                            . '|(^(6011)\d{13,16}$)|(^(65)\d{11,13}$)|(^(65)\d{15,18}$)'
-                            . '|(^(49030)[2-9](\d{10}$|\d{12,13}$))|(^(49033)[5-9](\d{10}$|\d{12,13}$))'
-                            . '|(^(49110)[1-2](\d{10}$|\d{12,13}$))|(^(49117)[4-9](\d{10}$|\d{12,13}$))'
-                            . '|(^(49118)[0-2](\d{10}$|\d{12,13}$))|(^(4936)(\d{12}$|\d{14,15}$))/',
                     // Visa
                     'VI'  => '/^4[0-9]{12}([0-9]{3})?$/',
                     // Master Card
                     'MC'  => '/^5[1-5][0-9]{14}$/',
                     // American Express
                     'AE'  => '/^3[47][0-9]{13}$/',
-                    // Discovery
-                    'DI'  => '/^6011[0-9]{12}$/',
-                    // JCB
-                    'JCB' => '/^(3[0-9]{15}|(2131|1800)[0-9]{11})$/'
+                    // Discover Network
+                    'DI'  => $discoverNetworkRegexp,
+                    // Dinners Club (Belongs to Discover Network)
+                    'DICL' => $discoverNetworkRegexp,
+                    // JCB (Belongs to Discover Network)
+                    'JCB' => $discoverNetworkRegexp,
+
+                    // Maestro & Switch
+                    'SM' => '/(^(5[0678])\d{11,18}$)|(^(6[^05])\d{11,18}$)|(^(601)[^1]\d{9,16}$)|(^(6011)\d{9,11}$)'
+                    . '|(^(6011)\d{13,16}$)|(^(65)\d{11,13}$)|(^(65)\d{15,18}$)'
+                    . '|(^(49030)[2-9](\d{10}$|\d{12,13}$))|(^(49033)[5-9](\d{10}$|\d{12,13}$))'
+                    . '|(^(49110)[1-2](\d{10}$|\d{12,13}$))|(^(49117)[4-9](\d{10}$|\d{12,13}$))'
+                    . '|(^(49118)[0-2](\d{10}$|\d{12,13}$))|(^(4936)(\d{12}$|\d{14,15}$))/'
                 );
 
                 foreach ($ccTypeRegExpList as $ccTypeMatch=>$ccTypeRegExp) {
diff --git js/prototype/validation.js js/prototype/validation.js
index a2dad07..700a472 100644
--- js/prototype/validation.js
+++ js/prototype/validation.js
@@ -850,11 +850,12 @@ function parseNumber(v)
 Validation.creditCartTypes = $H({
 //    'SS': [new RegExp('^((6759[0-9]{12})|(5018|5020|5038|6304|6759|6761|6763[0-9]{12,19})|(49[013][1356][0-9]{12})|(6333[0-9]{12})|(6334[0-4]\d{11})|(633110[0-9]{10})|(564182[0-9]{10}))([0-9]{2,3})?$'), new RegExp('^([0-9]{3}|[0-9]{4})?$'), true],
     'SO': [new RegExp('^(6334[5-9]([0-9]{11}|[0-9]{13,14}))|(6767([0-9]{12}|[0-9]{14,15}))$'), new RegExp('^([0-9]{3}|[0-9]{4})?$'), true],
-    'SM': [new RegExp('(^(5[0678])[0-9]{11,18}$)|(^(6[^05])[0-9]{11,18}$)|(^(601)[^1][0-9]{9,16}$)|(^(6011)[0-9]{9,11}$)|(^(6011)[0-9]{13,16}$)|(^(65)[0-9]{11,13}$)|(^(65)[0-9]{15,18}$)|(^(49030)[2-9]([0-9]{10}$|[0-9]{12,13}$))|(^(49033)[5-9]([0-9]{10}$|[0-9]{12,13}$))|(^(49110)[1-2]([0-9]{10}$|[0-9]{12,13}$))|(^(49117)[4-9]([0-9]{10}$|[0-9]{12,13}$))|(^(49118)[0-2]([0-9]{10}$|[0-9]{12,13}$))|(^(4936)([0-9]{12}$|[0-9]{14,15}$))'), new RegExp('^([0-9]{3}|[0-9]{4})?$'), true],
     'VI': [new RegExp('^4[0-9]{12}([0-9]{3})?$'), new RegExp('^[0-9]{3}$'), true],
     'MC': [new RegExp('^5[1-5][0-9]{14}$'), new RegExp('^[0-9]{3}$'), true],
     'AE': [new RegExp('^3[47][0-9]{13}$'), new RegExp('^[0-9]{4}$'), true],
-    'DI': [new RegExp('^6011[0-9]{12}$'), new RegExp('^[0-9]{3}$'), true],
-    'JCB': [new RegExp('^(3[0-9]{15}|(2131|1800)[0-9]{11})$'), new RegExp('^[0-9]{3,4}$'), true],
+    'DI': [new RegExp('^(30[0-5][0-9]{13}|3095[0-9]{12}|35(2[8-9][0-9]{12}|[3-8][0-9]{13})|36[0-9]{12}|3[8-9][0-9]{14}|6011(0[0-9]{11}|[2-4][0-9]{11}|74[0-9]{10}|7[7-9][0-9]{10}|8[6-9][0-9]{10}|9[0-9]{11})|62(2(12[6-9][0-9]{10}|1[3-9][0-9]{11}|[2-8][0-9]{12}|9[0-1][0-9]{11}|92[0-5][0-9]{10})|[4-6][0-9]{13}|8[2-8][0-9]{12})|6(4[4-9][0-9]{13}|5[0-9]{14}))$'), new RegExp('^[0-9]{3}$'), true],
+    'JCB': [new RegExp('^(30[0-5][0-9]{13}|3095[0-9]{12}|35(2[8-9][0-9]{12}|[3-8][0-9]{13})|36[0-9]{12}|3[8-9][0-9]{14}|6011(0[0-9]{11}|[2-4][0-9]{11}|74[0-9]{10}|7[7-9][0-9]{10}|8[6-9][0-9]{10}|9[0-9]{11})|62(2(12[6-9][0-9]{10}|1[3-9][0-9]{11}|[2-8][0-9]{12}|9[0-1][0-9]{11}|92[0-5][0-9]{10})|[4-6][0-9]{13}|8[2-8][0-9]{12})|6(4[4-9][0-9]{13}|5[0-9]{14}))$'), true],
+    'DICL': [new RegExp('^(30[0-5][0-9]{13}|3095[0-9]{12}|35(2[8-9][0-9]{12}|[3-8][0-9]{13})|36[0-9]{12}|3[8-9][0-9]{14}|6011(0[0-9]{11}|[2-4][0-9]{11}|74[0-9]{10}|7[7-9][0-9]{10}|8[6-9][0-9]{10}|9[0-9]{11})|62(2(12[6-9][0-9]{10}|1[3-9][0-9]{11}|[2-8][0-9]{12}|9[0-1][0-9]{11}|92[0-5][0-9]{10})|[4-6][0-9]{13}|8[2-8][0-9]{12})|6(4[4-9][0-9]{13}|5[0-9]{14}))$'), new RegExp('^[0-9]{3}$'), true],
+    'SM': [new RegExp('(^(5[0678])[0-9]{11,18}$)|(^(6[^05])[0-9]{11,18}$)|(^(601)[^1][0-9]{9,16}$)|(^(6011)[0-9]{9,11}$)|(^(6011)[0-9]{13,16}$)|(^(65)[0-9]{11,13}$)|(^(65)[0-9]{15,18}$)|(^(49030)[2-9]([0-9]{10}$|[0-9]{12,13}$))|(^(49033)[5-9]([0-9]{10}$|[0-9]{12,13}$))|(^(49110)[1-2]([0-9]{10}$|[0-9]{12,13}$))|(^(49117)[4-9]([0-9]{10}$|[0-9]{12,13}$))|(^(49118)[0-2]([0-9]{10}$|[0-9]{12,13}$))|(^(4936)([0-9]{12}$|[0-9]{14,15}$))'), new RegExp('^([0-9]{3}|[0-9]{4})?$'), true],
     'OT': [false, new RegExp('^([0-9]{3}|[0-9]{4})?$'), false]
 });