Objective: (a) To evaluate the effect of a cognitive-behavioural inpatient treatment and (b) to analyse the differential efficacy of an additional ("soma") group management training of somatisation. Methods: The final sample consisted of 191 patients with somatisation syndrome (patients with at least eight DSM-IV somatoform symptoms). Patients were randomly assigned to (I) "standard treatment+sonia" or (II) "standard treatment+relaxation training." A waiting control group consisted of 34 patients. All patients were diagnosed with a structured clinical interview for DSM-IV and received an interview on medical consulting behaviour and questionnaires concerning somatoform symptoms, general psychopathology, subjective health status, and life satisfaction. Results: Results show high impairment of the sample prior to treatment. At the 1-year follow-up, all outcome criteria were significantly reduced. The differential effect of the additional soma treatment was significant only for a reduction of visits to the doctor. Greatest longitudinal effect sizes were found for the reduction of somatoform symptoms. Conclusion: Considering the subjects' high initial impairment, the outcome results are encouraging. The specific effect on health care use highlights the socioeconomic relevance. (C) 2004 Elsevier Inc. All rights reserved.