BACKGROUND: The night clinic which is part of the psychiatric department of the University of Zurich is a part-time treatment option with psychiatric treatment and support in the evening. This study aimed to characterize the patients and detect different functions of the treatment setting. METHODS: Data of 253 patients covering a six-year period from 2008 up to 2013 were retrospectively assessed using descriptive methods. Subgroups according to the situation before admission and after discharge were compared. RESULTS: Patients admitted from home differed considerably from those who were transferred from a psychiatric ward concerning sociodemographic and clinical factors. They were more frequently single, unemployed, received disability funds and suffered from a psychotic disorder. They were also more likely to be discharged in a supported housing condition. CONCLUSIONS: The night clinic serves as an alternative to full inpatient treatment for individuals who have work as well as a rehabilitative option for homeless patients with severe mental illness. It contributes to a reduction of avoidance of inpatients stays for those groups of patients.