diff --git a/math_captcha/math_captcha.module b/math_captcha/math_captcha.module
index 52a7cfc5542210d05ced98e8be0a9d2f718543b4..41e83d4314136b7c1f869d4cd6f25ad3865f519b 100644
--- a/math_captcha/math_captcha.module
+++ b/math_captcha/math_captcha.module
@@ -40,8 +40,8 @@ function math_captcha_captcha($op, $captcha_type='') {
     case 'list':
       return array('Math CAPTCHA');
     case 'generate':
-      require_once('math_captcha.challenge.inc');
       if ($captcha_type == 'Math CAPTCHA') {
+        require_once('math_captcha.challenge.inc');
         // get the available challenges
         $challenges = array_filter(_math_captcha_enabled_challenges());
         $challenge = $challenges[array_rand($challenges)];