Eighty-five MR examinations were carried out on both breasts of 72 patients. A special surface coil was used. The results were compared with the findings of mammography and with the post-operative findings. There were 16 fibrocystic mastopathies, seven isolated cysts, 22 fibro-adenomas and 25 carcinomas. Differentiation between fibro-adenomas and carcinomas is only possible on the basis of morphological criteria. Cysts and fibrocystic mastopathies can be identified with certainty. Typical patterns of the various pathological conditions are described, but these will have to be confirmed by the study of a larger number of patients, in order to make them statistically significant. The advantage of MR consists in the simultaneous demonstration of the thoracic wall and the axilla.