Fifty-nine women with postmenopausal spinal osteoporosis and back pain were instructed in a treatment program that included extension exercises (E) for 25 patients, flexion exercises (F) for 9, combined (E + F) exercises for 19, or no therapeutic exercises (N) for 6. Ages ranged from 49 to 60 years (mean, 56 years). Follow-up ranged from one to six years (means for the groups, 1.4 to 2 years). All patients had spine x-ray studies before treatment and at follow-up, at which time any further wedging and compression fractures were recorded. Additional fractures occurred as follows: group E, 16%; F, 89%; E + F, 53%; and N, 67%. In comparison with group E, the occurrence of wedging or compression fractures was significantly higher in group F (p less than 0.001) and group E + F (p less than 0.01). This study suggests that a significantly higher number of vertebral compression fractures occur in patients with postmenopausal osteoporosis who followed a flexion exercise program compared with those using extension exercises. Extension or isometric exercises seem to be more appropriate for patients with postmenopausal osteoporosis.