The authors report the results obtained in two different series of cases examined by means of mammography in 1968/74 and in 1987/89. All patients had histologically proven breast cancer. The first series of cases included 183 patients who were examined with a mammographic unit with fixed anode, 0.6 x 0.6 mm focal spot, and 25-40 cm FFD. The second series included 152 patients who were examined with a last-generation mammographic unit with turning anode, 0.3 x 0.3 mm focal spot, 50-65 cm FFD, and radiographic magnification. Lesion staging in the first group went as follows: 10% of patients were T1, and 90% were in more advanced stages; in the second series, 42% were T1 and 52% were in more advanced stages. Mammographic accuracy was 83% in the first series and 84.8% in the second series. The main mammographic features of the lesions and their incidence were analyzed. In 11 patients examined with a last-generation unit, breast cancer was diagnosed for the presence of indirect signs which had not been demonstrated with the older unit. In conclusion, last-generation mammographic units allow an earlier diagnosis to be made, and most signs of breast cancer to be promptly demonstrated.