The effectiveness of psychosomatic therapy for asthma patients is difficult to prove. We tried to solve this problem in a new way by means of a cost-benefit analysis. To draw up such an analysis, we selected 22 patients capable of working out of a total of 57 patients with asthma bronchiale at the Heidelberg Medical Hospital, who were interested in participating for one year in a psychosomatic coping group therapy. These 22 patients were divided into two groups. The distribution of the relevant individual parameters in both groups was similar. We subjected the patients to three medical and psychodiagnostic examinations: one before treatment was started, a second after the first year of treatment and a third one and a half years later. Additional data were gathered from health insurance organisations and General Practitioners. Despite the bad prognoses of our patients, those treated, when compared to the untreated patients, had a significant reduction in the number of working days lost and a considerable decrease in the number of working days hospitalized. The savings resulting from these reductions were compared with the sum expended for group therapy; we found a cost-benefit ratio of 1:5. These results indicate that a cost-benefit analysis may be very helpful in evaluating the effectiveness of some psychosomatic treatment techniques. Moreover, coping group therapy completes the medical standard therapy of patients with bronchial asthma and is thus a means of reducing the high medical treatment costs of asthma patients.