The influence of radiation and/or chemotherapy on locoregional tumor control and survival in patients treated for recurrent breast cancer after radical or modified radical mastectomy is retrospectively evaluated in 164 patients treated between 1972 and 1983 at the University of Texas M. D. Anderson Hospital. Treatment consisted of radiation alone in 57 patients, chemotherapy alone in 50 patients, and a combination of radiation and chemotherapy in 57 patients. Important differences in the composition of these three groups include a preponderance of postmenopausal women (44% vs. 32%) and more patients with four or more positive axillary nodes at the time of initial mastectomy (32% vs. 18%) in the radiotherapy group. Locoregional control of recurrent cancer was achieved in 65% of patients with radiotherapy compared to 46% of patients with chemotherapy (P = 0.049) and 67% with chemotherapy and radiotherapy. The addition of chemotherapy produced a trend toward improved disease-free survival rates. The two prognostic factors affecting tumor control and survival in this study are the tumor burden of the recurrence and the histologic axillary node status at the time of the initial mastectomy.