The results are reported of a selected series of 41 patients with medullary carcinoma of the breast, treated with primary radiotherapy with (24 patients) or without (17 patients) adjuvant chemotherapy. Complete responses to radiotherapy occurred with moderate doses (67% of the patients had a complete response after a dose of 55-60 Gy) and were increased by the addition of an irradiation boost. The 6-year actuarial free of local recurrence survival, metastase-free survival and survival rates were 86, 83, and 83%, respectively. The 6-year actuarial probability of living with breast preserved was 72%. Recurrences and survivals were not influenced by the tumor size or clinical axillary node status. Adjuvant chemotherapy had no effect on the rate of recurrence or survival.