SUMMARYTwelve patients with chronic renal failure and osteitis fibrosa were treated for periods of 1–9 months with thrice‐weekly injections of 10–200 iu salmon calcitonin. Treatment had no significant effects on symptoms of bone disease and side effects were common. A transient fall in plasma alkaline phosphatase levels occurred in only three patients, and both plasma alkaline phosphatase and hydroxyproline levels rose in the majority of patients. Radiographic signs of hyperparathyroidism increased in seven of the nine patients treated for longer than 3 months. Paired bone biopsy specimens in nine patients showed significant increases in osteoblast counts, but no changes in the indices of resorption. These treatment‐induced changes were reversed when treatment with 1,25‐dihydroxyvitamin D3was substituted for calcitonin. The use of this regimen of salmon calcitonin is not recommended in the long‐term management of hyperparathyroid bone disease in chronic re