diff --git a/src/USPSBase.php b/src/USPSBase.php
index 83653ba..4441fb9 100644
--- a/src/USPSBase.php
+++ b/src/USPSBase.php
@@ -12,7 +12,7 @@
  */
 abstract class USPSBase
 {
-    const LIVE_API_URL = 'http://production.shippingapis.com/ShippingAPI.dll';
+    const LIVE_API_URL = 'https://secure.shippingapis.com/ShippingAPI.dll';
     const TEST_API_URL = 'http://production.shippingapis.com/ShippingAPITest.dll';
 
     /**