The Defence Mental Health Services(DMHS) provide an occupationally focused service for the UK armed forces when deployed and when at home. Although much of the work is similar to that carried out by National Health Service community mental health teams, there are many unique aspects to working with the military. Although carrying out operational duties is a key function of the armed forces, the majority of cases managed by the DMHS are not related to traumatic exposures; instead, adjustment, mood and substance use disorders form the bulk of the case work. However, DMHS personnel carry out a considerable amount of psychological education and command liaison functions to support the concept that the psychological welfare of troops is primarily a chain of command responsibility. This article outlines the structure and function of the DMHS and its approach to risk management.