The diagnostic capabilities of a small-size low-field (0.2-T) MR unit with a dedicated coil were investigated in the study of expansive lesions of the hand and wrist. Twenty-five patients suffering from the following diseases were examined: synovial cyst (6 patients), ganglion cyst (4), acute suppurative tenosynovitis (3), stenosing tenosynovitis (2), arteriovenous fistula (1), lipoma (1), fibrolipoma (2), chondroma (1), glomus tumor (1), fibromatosis palmaris (3), villonodular synovitis (1). Spin Echo (SE) and Gradient Echo (GE) scans were performed on all patients. The MR findings were compared with US, surgical and pathologic results. In synovial and ganglion cysts, acute suppurative and stenosing tenosynovitis, fibromatosis palmaris, fibrolipoma and lipoma, MRI showed typical patterns. In arteriovenous fistula, chondroma, glomus tumor and villonodular tenosynovitis, an accurate diagnosis could not be made: in these cases US failed to yield unquestionable results and the lesions could be diagnosed only at pathology. MRI yielded very accurate information as to lesion site and relationship with the surrounding structures; this kind of information, which is extremely important for the surgical approach, is not always provided by US. Low-field MRI can be considered a valuable diagnostic tool in the study of some expansive lesions of the hand and wrist. In other lesions this method can play a major role for both their characterization and the surgical approach.