One hundred twenty pathologically confirmed operable Stage III breast cancer patients were randomized to receive either postoperative radiotherapy or chemotherapy, or a combination of these, with or without levamisole immunotherapy. Radiotherapy was given to regional lymph nodes and chest wall. Chemotherapy consisted of six cycles of vincristine, doxorubicin, and cyclophosphamide. Radiotherapy provided local and chemotherapy systemic control over the tumor, but the best patient-saving results were achieved with a combination of radiotherapy and chemotherapy. This clinical trial was commenced in 1976, and the first 60 of 120 patients also received oral levamisole, 150 mg/day, on 2 consecutive days weekly as immunotherapy. All patients were followed for at least 5 years. At this stage levamisole seems to increase disease-free and overall survival in all three treatment arms (radiotherapy, chemotherapy, combined treatment). Significance is reached in disease-free survival (P = 0.035) and overall survival, adjusted for all other treatment modalities (P = 0.019).