A review of the reports in the literature concerning the incidence of sarcoma in bones affected by osteitis deformans suggests that this complication may not be as common as the original work of Paget1 indicated. Osteitis deformans is a comparatively rare disease, and in 1927, Bird2 found that the incidence in the larger hospitals of Boston was only 1 in every 15,000 patients admitted. This agreed with the results reported by Da Costa, Funk, Bergeim and Hawk,3 who observed only 3 cases among 38,000 patients admitted to the Jefferson Hospital in Philadelphia. In 1901, Packard, Steele and Kirkbride4 collected 67 instances of osteitis deformans, of which 5, or about 7.5 per cent, were complicated by sarcoma of the bone. Higbee and Ellis5 stated that at least 5 of 158 instances of Paget's disease reported up to January, 1911, were associated with sarcoma of the bone,