This study was undertaken to document and better defined this condition to help clarify this clinical and radiographical appearances by the analysis of clinical and radiographical features of fibro-osseous lesions in the jaws. A study was made of a series of 128 cases with fibro-osseous lesions. The obtained results were as follows. 1. Fibrous dysplasia of the jaws occurred with equal predilection for males and females. But the females occurred in 68% of cemento-ossifying fibroma and 75% of periapical cemental dysplasia. 2. 43% of fibrous dysplasia and 32% of cemento-ossifying fibroma occurred in the 2nd decades and 33% of periapical cemental dysplasia in 5th decades. 3. 62% of fibrous dysplasia occurred in the maxilla, 73% of cemento-ossifying fibroma in mandible, 90% of periapical cemental dysplasia in mandible. 4. 98% of fibrous dysplasia occurred in premolar-molar region, 77% of cemento-ossifying fibroma in molar region, 68% of periapical cemental dysplasia in incisor region. 5. In serial radiographic features, mature stage were 55% of fibrous dysplasia, 45% of cemento-ossifying fibroma, 59% of periapical cemental dysplasia. 6. 87% of fibrous dysplasia had monostotic lesion, 67% of periapical cemental dysplasia had multiple lesions. 7. In fibrous dysplasia and cemento-ossifying fibroma, migration of tooth occurred in 61.7% and 36.4%, retention of tooth occurred in 4.3% and 9.1%, loss of lamina dura occurred in 6.4% and 9.1%, and root resorption had not occurred in fibrous dysplasia, but occurred in 18% of cemento-ossifying fibroma, displacement of mandibular canal occurred in 14.9% and 31.8%.