Objectives. Several studies suggest a beneficial overall effect of spa therapy in chronic musculoskeletal diseases. The present open controlled study investigated the effects of spa therapy at Bourbonne-Les-Bains, France, in patients with hip or knee osteoarthritis or low back pain. Patients and methods. In 1998, 102 men and women older than 50 years were included in the study. All had low back pain or lower limb osteoarthritis, and none had contraindications to spa therapy. Quality of life was assessed three times at intervals of 4 weeks, twice before and once immediately after 3 weeks of spa therapy, using the Duke Health Profile (five dimensions and five dysfunctions). Results. Mean age was 66.4 years, and 67% of the patients were women. Quality of life was markedly decreased as compared to the population at large (1996, CFES). The two pretreatment evaluations produced similar quality-of-life scores. Spa therapy was associated with significant improvements in overall quality of life (P=0.004), self-esteem (P=0.009), and pain (P=0.01). Conclusion. These findings support those of other studies conducted in France and in other European countries. They indicate that patients report meaningful improvements in their quality of life after spa therapy.