This study focuses on the role of the Mental Health Officer and the topic of gender. Twenty Mental Health Officers working for the City of Edinburgh Council Social Work Department were interviewed, ten female and ten male. Meanings of gender are explored in relation to Mental Health Officers’ understandings of their professional role and their membership of a social work organisation. Meanings of gender are also explored in relation to their personal view and these are found to overlap with their professional responsibilities. This thesis uses a qualitative approach informed by feminist theory and methodology Schutzian phenomenology has been drawn on to explore categorisation and experience. Meanings of gender arise in relation to three areas: personal biography, cultural context, and social institution. Informants’ personal biographies emphasise the sense of uniqueness of individuals and raised gender-related topics. These topics are sexuality issues, age, emotions, and the male personal gender. The cultural context of gender, or gender culture, is studied from various informants’ views, and shared experiences based on gender groupings are discussed. At the social institutional level, the issues of vertical and horizontal segregation is raised by several informants. Informants also discuss their working relations with medical colleagues, particularly medical doctors. Key practice issues and policy implications arise from the study. These relate firstly, to reported working practice. 1. substitution of a mental health social worker for one of the other sex 2. joint working 3. avoidance This study also raises more general issues in relation to mental health social work. Six areas are explored in the thesis: children, heterosexuality, commonality, patriarchy, age, and emotion.