diff --git a/system/core/CodeIgniter.php b/system/core/CodeIgniter.php
index 99c261e..39a4d7f 100644
--- a/system/core/CodeIgniter.php
+++ b/system/core/CodeIgniter.php
@@ -53,7 +53,14 @@
  *  Load the framework constants
  * ------------------------------------------------------
  */
-	require(APPPATH.'config/constants'.EXT);
+	if (file_exists(APPPATH.'config/'.ENVIRONMENT.'/constants'.EXT))
+	{
+		require(APPPATH.'config/'.ENVIRONMENT.'/constants'.EXT);
+	}
+	else
+	{
+		require(APPPATH.'config/constants'.EXT);
+	}
 
 /*
  * ------------------------------------------------------
@@ -365,4 +372,4 @@
 
 
 /* End of file CodeIgniter.php */
-/* Location: ./system/core/CodeIgniter.php */
+/* Location: ./system/core/CodeIgniter.php */
\ No newline at end of file