Control of parasites in cats is a key responsibility for veterinary professionals. The area is complicated because therapy must be suited to each cat, there is an overwhelmingly large choice of parasiticide products on the market and very intense promotional activity by drug companies. The aim of this module is to help veterinary professionals use parasiticides rationally. It covers the five main parasites that affect cats in the UK and the parasiticide drugs used to treat them, and outlines the different approaches to parasite control.