A 15-year-old patient with hyperparathyroidism is presented, with severe bone deformities. The appearance of the skeleton in the roentgenograms suggested late rickets. Surgical exploration of the neck disclosed a parathyroid adenoma. This was removed, and the patient is now, 6 months later, apparently cured. No evidence of renal disease or of intestinal malabsorption could be demonstrated pre- or postoperatively.