BACKGROUND There are no studies on economic issues concerning rehabilitation exercises for shoulder pain. OBJECTIVE The aim of the study was to investigate sick leave and the associated costs after a medical exercise therapy programme in patients with longstanding subacromial pain/impingement. METHODS A randomised controlled trial in which 61 patients were randomly assigned either to a high-dosage medical exercise therapy group (HD) (n=31) or to a low dosage exercise therapy group (LD) (n=30). Both groups were given three treatments a week over 3 months. The differences between the groups were number of repetitions, number of sets and time performing global aerobic exercises. RESULTS The outcome for the HD group was significantly (p<0.05) better compared to the LD group. The reduction in costs for sick leave for the HD group was 59.1%, whereas for the LD group, the reduction was only 42.3%, which is a significant difference. CONCLUSION In patients with longstanding subacromial pain, HD medical exercise therapy might be an efficient treatment approach.