The purpose of this study was to evaluate MRI diagnostic accuracy in rheumatoid arthritis (RA), to compare MRI and radiological findings and to correlate these findings with the clinical and serological profile of the disease. The hands of 24 patients (20 females, 4 males) affected with typical RA (ARA criteria) were studied using a tomograph Magnetom 1.0 T Siemens. Two patients affected with RA refractory to conventional second-line drugs who received a bolus of methylprednisolone (1 g) were studied before and after such treatment. The hands of healthy volunteers were examined as controls. Besides MRI study all patients underwent: (1) radiological examination of the hands performed with a standard technique and (2) clinical and serological investigation aimed at characterizing diseases activity and extent. The radiographic and MRI findings were evaluated by two different observers who found 15 pathological elementary lesions and assigned a MRI and a radiological score to each patient. MRI exhibited significantly higher accuracy than radiography in evaluating rheumatoid soft-tissue changes and in detecting minimal skeletal lesions, while severe skeletal lesions were better detected by radiology. No correlation was found between pathological MRI findings, radiological results and clinical or serological data. A significant drop in soft-tissue effusion was observed after methylprednisolone pulse in two patients. This study confirms MRI potential in the study of rheumatoid joint lesions and in the early detection of minimal soft-tissue changes. Its use appears to be suitable for accurate monitoring of RA patients under specific therapy.