A syndrome of back and loin pain produced by impingement of the lowest rib against the iliac crest is described in six patients. All had noticed a significant loss of height and five had osteoporosis of the vertebral column. It is suggested that mechanical irritation of the lowest rib against the iliac crest was the cause of the pain and that subperiosteal resection of the outer two-thirds of the rib would stop this irritation and relieve the symptoms. The six patients who underwent resection of the twelfth rib all obtained relief of symptoms; in one patient the eleventh rib also was resected. At latest review 5 to 34 months postoperatively there has been no recurrence of symptoms.