A subanalysis of results from a randomized, double-blind, placebo-controlled, parallel-group, 2-year study was conducted to evaluate the response of individual patients to therapy with 200 IU/d calcitonin salmon nasal spray compared with placebo in postmenopausal women who had low bone mass. All patients received 500 mg/d of oral supplemental calcium. A response to therapy was defined as an increase from baseline in lumbar vertebral bone mineral density, measured by use of dual-energy x-ray absorptiometry, at the end of 2 years of treatment. Of 41 valid completers (ie, patients who met the entry criteria, were compliant with the protocol, and completed the study) treated with calcitonin salmon nasal spray, 31 (76%) responded positively to treatment. Of 40 valid completers who received placebo, 25 (63%) lost bone mass (P = 0.001 between groups). The relative risk of bone loss for patients receiving calcitonin salmon nasal spray was 0.19 (95% confidence interval, 0.07 to 0.50), representing an 81% risk reduction. This subanalysis demonstrates that the benefits of calcitonin salmon nasal spray therapy were seen in the majority of women studied. Calcitonin salmon nasal spray represents an effective therapeutic alternative for osteoporotic women more than 5 years postmenopause who reject or cannot tolerate estrogens or for whom estrogens are contraindicated.