I have been working on a new WordPress theme (to be released this week) and in one of the admin screens – I needed to get the category name by using the category ID. To do this (in or outside of the loop):
<?php get_cat_name( $cat_id ) ?>
Super simple – super helpful.
Reference: http://codex.wordpress.org/Function_Reference/get_cat_name

Thanks!
Needed this!
Thanks, simple and really really useful in daily use.
Thanks!
Really very helpful!!
Wowh.. that so simple but so usefull….
Very2 I need!
thanks ^^
Thanx a lot
Totally awesome. i Goggled the simplest way to do this and i landed on correct page.
Thanks Mate.
Nice post it helped me a lot. Thanks…