diff --git a/lib/mysql.js b/lib/mysql.js
index 9f57472..5e44138 100644
--- a/lib/mysql.js
+++ b/lib/mysql.js
@@ -129,7 +129,7 @@ require('util').inherits(MySQL, SqlConnector);
 MySQL.prototype.query = function (sql, callback) {
   var self = this;
   if (!this.dataSource.connected) {
-    return this.dataSource.on('connected', function () {
+    return this.dataSource.once('connected', function () {
       this.query(sql, callback);
     }.bind(this));
   }