This text complements current legislation and guidance and provides practical advice about achieving an appropriate system of pharmacovigilance. This guide was primarily developed for UK Marketing Authorisation Holders (MAHs). It will also be of great interest to pharmacovigilance consultants. The use of third-party service providers for pharmacovigilance activities is quite common, particularly for smaller organisations which do not have in-house pharmacovigilance expertise. The guide references European legislation and guidance and so should be applicable across Europe.