Have you tried File => Properties => (tab) Statistics?
If you want an enhanced version, you can install
http://billdilworth.mvps.org/Add-ins.htm#WordCountPlus
This add-in is run from the tools menu in PowerPoint.

Signature
Bill Dilworth
A proud member of the Microsoft PPT MVP Team
Users helping fellow users.
http://billdilworth.mvps.org
-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_
vestprog2@ Please read the PowerPoint FAQ pages.
yahoo. They answer most of our questions.
com www.pptfaq.com
.
> Can you count the words in a powerpoint slide document?