Pigmented villonodular synovitis is a rare proliferating process of the synovium, tendon sheaths and bursae usually affecting the bone and joints. The disease can be localized or diffuse. Patients with this condition typically present with symptoms of mild discomfort and associated swelling of the involved joint. However, the spectrum of presentations is broad. Diagnosis of Pigmented villonodular synovitis can be clinically difficult, and plain radiographs are usually nonspecific. Magnetic resonance imaging is a highly diagnostic modality in characterizing pigmented villonodular synovitis when it contains hemosiderin deposits exhibiting low signal intensity on all pulse sequences. Magnetic resonance imaging is recommended for accurate preoperative staging of the disease and for follow up after treatment. I report a case of pigmented nodular synovitis in the knee joint, with review of literatures.