Pigmented villonodular synovitis is a rare disease which is usually benign but sometimes causes wide articular destruction. Since its clinical signs and symptoms are not specific, the disease may remain undiagnosed, sometimes for long periods. The diagnosis is generally confirmed at pathology, but it can now be strongly suggested by modern imaging methods. Standard radiography may be normal, with a variety of images. Arthrography with an opaque material points to the diagnosis in only two-third of the cases. Ultrasonography is non-specific. Computed tomography may be strongly suggestive of pigmented villonodular synovitis in cases with high density synovia; when coupled with arthrography, it provides detailed information on lesions of the cartilage and on extension of the synovial process. The most sensitive and specific method is magnetic resonance imaging, the most characteristic sign being low-intensity signal areas on T1- and T2-weighted sequences, corresponding to haemosiderin-loaded nodules. Performed after standard radiography, magnetic resonance imaging is the best examination method for the diagnosis and pretherapeutic evaluation of suspected villonodular synovitis.