Interaction with companion animals is now known to confer health and social benefits to people of all ages, whether living in the community or living within an institution. Carefully-planned Animal Assisted Therapy (AAT) programmes can be introduced to enhance the therapeutic milieu and as an adjunct to client care to help address diverse health and social needs. This paper provides an introductory overview of the role of animals in institutions. The author draws on her experience with particular reference to a programme in a prison-based therapeutic community. The introduction of carefully planned AAT programmes would bring many benefits to prisoners, staff and ultimately to society. A multidisciplinary approach is emphasised. A consistent approach to animals in institutions is required and programmes should work to recognised standards. The effects of AAT on offenders requires more research including monitoring of recidivism. (PsycINFO Database Record (c) 2019 APA, all rights reserved)