OBJECTIVE In consultation liaison (CL) psychiatry and psychosomatics a multicenter documentation form for the assessment of clinical characteristics of patients and CL service delivery is urgently needed for health care planning and future mental health research. METHODS In several steps a joint working party of the psychosomatic and psycho-therapeutic societies in Germany (German College for Psychosomatic Medicine, German Society of Psychosomatic Medicine and Psychotherapy, General Medical Society for Psychotherapy) developed a documentation form for C-L service (CL-BaDo). The goals and quality criteria of the patient registration form are defined in an extended consensus process of C-L experts. A pool of formerly 60 items was reduced to 36 items collecting data concerning sociodemographic characteristics, referral information, anamneses, actual psychiatric and somatic status and diagnoses, C-L interventions and treatment recommendations. To enable comparisons, the formulation of items are adapted to existing inpatient and outpatient documentation forms (Psy-BaDo,EuroQA-CL). A special manual guides the coding of the CL-BaDo. RESULTS 16 CL services in Germany and Austria participated in the testing and pilot study of six months demonstrating the comprehensibility and fast completion of CL-BaDo and consultants' high acceptance of the form. A time-saving and user-friendly electronic version for data entry and data analyses was developed using hand-held technology. CONCLUSIONS The data of the CL-BaDo can be used for 1) quality management and communication purposes with referring departments and 2) for multicenter collaborative studies, mental health care management and care planning.