Ossifying fibroma is not a well recognized entity, and only rarely affects the long bones. The main differential diagnosis is with fibrous dysplasia and with adamantinoma, non-ossifying fibroma of the long bone. Ossifying fibroma seldom has even a moderate tendency to progress during childhood, but it recurs frequently after curettage or subperiosteal resection. Any progression of the lesion comes to an end after puberty. So, surgery should be delayed as long as possible. But, if the lesion is rapidly progressive, or if a patient has repeated fractures, it would be necessary to resort to wide extraperiosteal resection. We have experienced 7 cases of ossifying fibroma from Octover 1979 to November 1988. The results were as follows; 1. The male and female ratio, was 5 to 2 and six patients were at their first decade, and one patient was 13 years old. 2. The lesion site was six cases in the tibia, one case in the fibula. 3. In six patients, we had done wide resection with free-vasculaized fibular graft in five cases and wide resection of the distal one-third of the fibula in one case. Two patients among them had recurrence. One case of recurrence was performed incomplete wide resection with free vascularized fibular graft because the lesion was too close to the distal epiphysis of the tibia.