An instrument documenting the care process in in-patient psychiatric services within the German mental health care system has been developed (BADO). This paper reports on the development of a documentation system for all non-hospital based mental health services (day centres, community mental health centres, supported accommodation, work rehabilitation services for general adult psychiatric patients and people with substance misuse). The development process and the instrument (PC and paper and pencil version) are described. The documentation system (BADO-K) could be an important prerequisite for quality assurance in non-hospital based mental health care, and its structure ensures compatibility with the corresponding hospital-based documentation system.