In 107 patients with idiopathic scoliosis radiographs were performed under standard conditions immediately before and immediately after a 4-6 week in-patient exercise program at the Katharina-Schroth Hospital. The average angle of curvature as measured by the Cobb technique was 43.06 degrees (standard deviation = 22.87) before treatment and 38.96 degrees (SD = 23.00) after treatment. An improvement in the curve of 5 degrees or more was found in 43.93% of the patients, 53.27% were unchanged and in 2.8% the curve increased by 5 degrees or more. Altogether the improvements in curvature were highly significant. These results show that even in severe scoliosis the magnitude of the curve can be reduced by a specific rehabilitation program of physiotherapy.