A review of the radiographs of 26 patients with autosomal dominant osteopetrosis disclosed two distinct and strictly family-related radiographic types. Both types had universal osteosclerosis. In type 1 the most striking finding was pronounced sclerosis of the cranial vault while the spine was almost unaffected. In type 2 the sclerosis of the skull was most pronounced at the base, the vertebrae always had end-plate thickening, and in the pelvis the iliac wings contained convex arcs of sclerotic bone. Age and sex distribution did not differ between the types. Autosomal dominant osteopetrosis may be a heterogeneous group of inherited bone disorders.