An epidemiologic study was carried out in order to evaluate the effects of prevention programs at the workplace aimed at reducing back, neck, and shoulder morbidity among active workers. The intervention group included 275 workers in three occupational subgroups: hospital workers, warehouse workers, and office workers. The control group included 250 workers as comparable as possible to the intervention group. Comparisons were made, according to one-year changes in morbidity scores, for low back, upper back, neck, and shoulder disorders separately. An overall measure was also used. The one-year change in the overall measure was significantly different between the intervention group and the control group, indicating a positive effect of the prevention programs. Positive effects were stronger for some sites of pain and some occupational groups.