The aim of this study was to investigate the early effect of nasal salmon calcitonin on a bone-resorption marker, "Crosslaps", in postmenopausal osteoporotic women. In this randomized, single-blind and placebo-controlled study we included 78 postmenopausal women with osteoporosis, between 45 and 65 years of age, with at least 5 years duration of menopause. Patients were randomly divided into two groups, the treatment and the placebo groups. Patients in the treatment group were given 100 IU day(-1)nasal salmon calcitonin, 1,000 mg day(-1)s elemental calcium, and 400 IU day(-1) vitamin D. Patients in the placebo group took only 1,000 mg day(-1)elemental calcium, and 400 IU day(-1) vitamin D. The outcome measurements were urinary deoxypyridinoline, serum alkaline phosphatase, osteocalcin, and Crosslaps. The treatment group consisted of 39 patients whose mean age was 60.4 +/- 6 years and the placebo group included 39 patients with a mean age of 60.5 +/- 4.9 years. There was no significant difference between two groups in terms of demographic characteristics. The results of bone marker measurements were analyzed statistically. Crosslaps levels in the treatment group were significantly lower (P < 0.05) than in the placebo group. Other bone marker levels at the end of the study were not significantly lower (P > 0.05) than those at baseline in both treatment and placebo groups, however. Salmon calcitonin affects bone turnover within a few months and bone-resorption markers such as Crosslaps can be used to monitor the effect of nasal salmon calcitonin in the early phase of treatment for postmenopausal osteoporosis.