Synovial chondromatosis is a condition of metaplastic and focal formation of cartillage in the intimal layer of synovial membrane. The etiology is unknown. The cartilagenous foci become pedunculated and may be sequestrated into the synovial cavity to form loose body. The center of focus may calcify and ossify. Of the ten cases of synovial chondromatosis experiences by the authors, five cases invo1ved the knee joint, one case both knee joint, two cases the hip joint, two cases the elbow joint, one case the wrist joint. The diagnosis of synovial chondromatosis was made by the histopathological finding of the excised masses.