1. A report is given of a family suffering from dystrophia myotonica and familial Paget’s disease of bone.

2. Radiological changes in the skull occur in both disorders, which are quite dissimilar. Thickening of the calvarium, however, may be common to both.

3. The serum alkaline phosphatase is high in Paget's disease and normal in dystrophia myotonica.

4. In one patient the Paget's disease was complicated by the development of multiple sarcomata. Sarcomatous involvement of the vertebral column, observed in one of the cases, has not been recorded before.