From http://drupal.org/node/64279#module-exists : "module_exist() is now module_exists() For consistency with PHP function_exists, file_exists, etc. That's about all there is to say about that. :)" From my local copy of cvs: $ cd /cvs/contributions/modules $ grep -r module_exist\( . | wc -l 630 It would be nice to have a wrapper function in for one release cycle.