diff --git a/config/main.inc.php.dist b/config/main.inc.php.dist
index 6be1f1e5f..6d12e6024 100644
--- a/config/main.inc.php.dist
+++ b/config/main.inc.php.dist
@@ -183,6 +183,10 @@ $rcmail_config['sendmail_delay'] = 0;
 // Maximum number of recipients per message. Default: 0 (no limit)
 $rcmail_config['max_recipients'] = 0; 
 
+// Maximum allowednumber of members of an address group. Default: 0 (no limit)
+// If 'max_recipients' is set this value should be less or equal
+$rcmail_config['max_group_members'] = 0; 
+
 // add this user-agent to message headers when sending
 $rcmail_config['useragent'] = 'RoundCube Webmail/'.RCMAIL_VERSION;
 
diff --git a/program/localization/de_CH/messages.inc b/program/localization/de_CH/messages.inc
index be61cc78d..e0ca1c986 100644
--- a/program/localization/de_CH/messages.inc
+++ b/program/localization/de_CH/messages.inc
@@ -109,5 +109,7 @@ $messages['smtptoerror'] = 'SMTP Fehler ($code): Der Empfänger ("$to") konnte n
 $messages['smtprecipientserror'] = 'SMTP Fehler: Die Empfängerliste konnte nicht verarbeitet werden';
 $messages['smtperror'] = 'SMTP Fehler: $msg';
 $messages['emailformaterror'] = 'Ungültige E-Mail-Adresse: $email';
+$messages['toomanyrecipients'] = 'Zuviele Empfänger angegeben. Reduzieren Sie die Empfängeradressen auf $max.';
+$messages['maxgroupmembersreached'] = 'Die Anzahl Adressen in dieser Gruppe überschreitet das Maximum von $max';
 
 ?>
diff --git a/program/localization/en_US/messages.inc b/program/localization/en_US/messages.inc
index 1dfdb96ba..8822f302b 100644
--- a/program/localization/en_US/messages.inc
+++ b/program/localization/en_US/messages.inc
@@ -110,7 +110,8 @@ $messages['smtpfromerror'] = 'SMTP Error ($code): Failed to set sender "$from"';
 $messages['smtptoerror'] = 'SMTP Error ($code): Failed to add recipient "$to"';
 $messages['smtprecipientserror'] = 'SMTP Error: Unable to parse recipients list';
 $messages['smtperror'] = 'SMTP Error: $msg';
-$messages['emailformaterror'] = 'Incorrect e-mail address: $email';
+$messages['emailformaterror'] = 'Invalid e-mail address: $email';
 $messages['toomanyrecipients'] = 'Too many recipients. Reduce the number of recipients to $max.';
+$messages['maxgroupmembersreached'] = 'The number of group members exceeds the maximum of $max';
 
 ?>
diff --git a/program/steps/addressbook/groups.inc b/program/steps/addressbook/groups.inc
index df44703a9..eda258c6e 100644
--- a/program/steps/addressbook/groups.inc
+++ b/program/steps/addressbook/groups.inc
@@ -31,7 +31,12 @@ if ($RCMAIL->action == 'group-addmembers') {
   if (($gid = get_input_value('_gid', RCUBE_INPUT_POST)) && ($ids = get_input_value('_cid', RCUBE_INPUT_POST))) {
     $plugin = $RCMAIL->plugins->exec_hook('group_addmembers', array('group_id' => $gid, 'ids' => $ids, 'source' => $source));
     
-    if (!$plugin['abort'] && $CONTACTS->add_to_group($gid, $plugin['ids']))
+    $CONTACTS->set_group($gid);
+    $num2add = count(explode(',', $plugin['ids']));
+    
+    if (!$plugin['abort'] && ($maxnum = $RCMAIL->config->get('max_group_members', 0)) && ($CONTACTS->count()->count + $num2add > $maxnum))
+      $OUTPUT->show_message('maxgroupmembersreached', 'warning', array('max' => $maxnum));
+    else if (!$plugin['abort'] && $CONTACTS->add_to_group($gid, $plugin['ids']))
       $OUTPUT->show_message('contactaddedtogroup');
     else if ($plugin['message'])
       $OUTPUT->show_message($plugin['message'], 'warning');