Plgmented villonodular synovitis is a benigh lesion that develops in joint lining and is characterized by an exuberant inflammation. Many authors have discussed etiology, clinical and radiological features, pathology and treatment regarding the disease. This occurs most commonly in the knee joint as a monoarticular proliferative process, but rarely in the hip joint. It is a nonneoplastic disease but may develop as an aggressive local process with bone and joint destruction. Sometimes clinician can not detect it in early time because of its nonspecific clinical findings and misdiagnose it as sarcomatous process. So, early diagnosis of hip joint involvement is necessary because destruction of the femoral head and acetabulum is the ultimate outcome if treatment is not intiated. We report two cases of pigmented villonodular synovitis involving the hip joint, which were diagnosed and treated in our department.