Multidisciplinary teams (MDTs) are conventionally recommended in mental health care literature as an important way to offer holistic treatment provision to patients. This study aims to explore multidisciplinary teamwork in contemporary mental health settings, particularly what aids and hinders the process of multidisciplinary teamworking, and the social work contribution in such teams. In order to attain an in-depth exploration of these phenomena, a single case study design was employed. Within this design, data were generated through semi-structured interviews and structured observation of a mental health MDT in Ireland. These data were analysed using interpretative phenomenological analysis. The research highlights how the concept of mental illness is contested within this MDT, with the medical model dominant within an environment of fluid working arrangements. Professional role blurring and stereotyping were found to impact the division of labour on this team, with role negotiation found to be an integral part of retaining a professional's practice identity. This research raises concerns for social work's capacity to function within mental health MDTs in Ireland, and highlights ways in which social work educators might respond in order to empower Irish social workers to meet the challenges of mental health multidisciplinary teamworking.