From July of 1974 to June of 1978, 131 patients with Stage II carcinoma of the breast were randomly assigned to one of three treatment arms in order to assess the efficacy of adding immunotherapy to adjuvant chemotherapy. All patients had metastases in the axillary lymph nodes, but no clinical evidence of systemic disease. Prognostic factors were relatively equally distributed among the three treatment arms. All patients received adjuvant chemotherapy consisting of cytoxan, methotrexate, and 5-fluorouracil (CMF). In addition, patients received adjuvant immunotherapy consisting of Bacille Calmette Guerin (BCG) or BCG plus a tumor cell vaccine. This vaccine was a mixture of allogeneic breast cancer cell lines grown in tissue culture. Fourteen patients receiving tumor cell vaccine developed hepatitis B, leading to the abandonment of this arm of the study. Side effects of chemotherapy were tolerable. No statistically significant difference could be demonstrated in recurrence rate or survival. However, the two groups receiving adjuvant chemo-immunotherapy had a slightly shorter time to recurrence and lower overall survival. The use of chemo-immunotherapy as administered in this study did not improve the clinical course of patients with Stage II breast cancer and was associated with significant morbidity.