Psychiatric day care has a long tradition. However, psychotherapeutic day care institutions specialising in particular disorders or certain therapeutic approaches are still the exception. A day care unit for behaviour therapy was established at the Clinic for Psychiatry and Psychotherapy, University Hospital Hamburg-Eppendorf in 1998 as part of a complex inpatient, day care, and outpatient behaviour therapy unit. The immediate and high acceptance by patients and their doctors indicates a strong need of such a treatment setting. We present how this day care unit works and how it differs from the traditional psychiatric day care.