Ossifying fibroma is one of a group of fibro-osseous lesion which arises typically within the jaw bone and only rarely affects the long bones. In 1966, Kempson described two patients with ossifying fibroma of the tibia, noting its unique, aggressive local behavior. This rare lesion resembles monostotic fibrous dysplasia, but can be differentiated from it on histologic and clinical ground. Histologically, ossifying fibroma is characterized by osteoblasstic rimming spicules of bone within a fibrous stroma with evidence of the lamella transformation of bone, and clinically by, frequent recurrence and aggressive progression of the lesion. We experieced three cases of ossifying fibroma, two cases in the tibia and one case in the fibula. In case 1, recurrence was developed after local curettage and bone graft, so reoperation was performed at 11 months after the first opecation. The 2nd case was healed after wide curettage and free vascularized fibula graft, and the 3rd case being followed up after segmental resection of the fibula.