diff --git a/lib/irc-to-slack.js b/lib/irc-to-slack.js
index 7a31a73..535a2a9 100644
--- a/lib/irc-to-slack.js
+++ b/lib/irc-to-slack.js
@@ -14,6 +14,9 @@ var IrcToSlack = function(config) {
     'bannedKeywords': []
   });
 
+  this.config.bannedIRCNicks.join('|').toLowerCase().split('|');
+  this.config.bannedKeywords.join('|').toLowerCase().split('|');
+
   return this;
 };
 
@@ -32,12 +35,12 @@ IrcToSlack.prototype._sentToSlack = function(type, from, to, message) {
   var isNickExist = !!this.nameMap.getSlackNameByIrcNick(from);
   var bannedKeywords = this.config.bannedKeywords;
 
-  if (_.contains(this.config.bannedIRCNicks, username)) {
+  if (_.contains(this.config.bannedIRCNicks, username.toLowerCase())) {
     return;
   }
 
   for (var i=0,  len=bannedKeywords.length; i < len; i++) {
-    if (message.toLowerCase().indexOf(bannedKeywords[i].toLowerCase()) > -1) {
+    if (message.toLowerCase().indexOf(bannedKeywords[i]) > -1) {
       return;
     }
   }