Objective — to clarify whether it is expedient to divide edematous breast cancer into primary and secondary forms. Material and methods. This investigation studied and compared retrospectively the results of instrumental and postmortem examinations in 70 patients with edematous-infiltrative breast cancer (EIBC). Results. With the clinical introduction of digital mammography, the quality of diagnosis was found to be improved considerably, which could reveal a tumor lesion in the presence of breast edema in 77.7% of the patients while with the use of analog mammography, this figure did not exceed 35.3%. Ultrasonography revealed a lump in the breast in its edema in 76—85.1% of the patients. These results lend credence to the highest sensitivity of the technique versus mammography in revealing space-occupying lesions in the presence of tissue swelling. Examination of postoperative materials detected tumor tissue in 100% of the patients. Conclusion. There is no sufficient clinical and morphological evidence to divide EIBC into primary and secondary forms, which is most probably associated with the pitfalls of analog mammography.