This service evaluation comprised pre- and post measures with service users and their carers on admission to and discharge from an assessment and treatment (A&T) unit. The Behaviour Problems Inventory (BPI), Psychiatric Assessment Scale for Adults with Developmental Disabilities Checklist--Revised (PASSAD) and World Health Organisations Quality of Life Scale (WHO-QOL 8; adapted for people with intellectual disabilities) were used to evaluate outcomes of their admission to the unit. Significant improvements were found after admission in relation to behaviour that challenges (measured by the BPI), mental health symptoms (measured by the PASSAD) and quality of life (measured by the WHO-QOL). The importance of completing outcome measures as feedback for the service user, team and wider service managers are discussed, but also in this political context when the role of A&T units are being questioned, the importance of showing good practice and clinical outcomes for individuals.