diff --git a/phpseclib/System/SSH_Agent.php b/phpseclib/System/SSH_Agent.php
index 91c48b4f..c57c4b74 100644
--- a/phpseclib/System/SSH_Agent.php
+++ b/phpseclib/System/SSH_Agent.php
@@ -36,4 +36,4 @@
  * @internal  See http://api.libssh.org/rfc/PROTOCOL.agent
  */
 
-include_once 'SSH/Agent.php';
\ No newline at end of file
+require_once 'SSH/Agent.php';
\ No newline at end of file