diff --git a/lib/mysql.js b/lib/mysql.js
index 4bd4b55..1015465 100644
--- a/lib/mysql.js
+++ b/lib/mysql.js
@@ -34,7 +34,7 @@ exports.initialize = function initializeDataSource(dataSource, callback) {
   s.supportBigNumbers = (s.supportBigNumbers || false);
   s.timezone = (s.timezone || 'local');
 
-  if (!isNaN(s.connectionLimit)) {
+  if (isNaN(s.connectionLimit)) {
     s.connectionLimit = 10;
   }