Osteofibrous dysplasia of the tibia and fibula is not a well recognized entity. We have seen thirty-five patients with the disease. Twenty-two comparable cases have been reported in the literature with such diagnoses as ossifying fibroma, congenital fibrous dysplasia, and congenital fibrous defect of the tibia. The main differential diagnosis is with fibrous dysplasia and with adamantinoma of a long bone. Twelve of our patients had long-term follow-up and some of the lesions regressed spontaneously. Osteofibrous dysplasia seldom has even a moderate tendency to progress during childhood, but it recurs frequently after curettage or subperiosteal resection. Such recurrences generally are moderately progressive or not progressive at all. Any progression of the lesion comes to an end after puberty. Attempts at radical surgery either primarily or after recurrence do not seem to be necessary. Surgery should be delayed as long as possible and should be restricted to extensive lesions. The results of surgical treatment usually are good even in patients with a recurrence, fracture, or pseudarthrosis.