A prospective, randomized clinical trial of adjuvant treatment of 318 stage II breast cancer patients, using chemotherapy, the antiestrogen tamoxifen, and immunotherapy is reported at 48 months follow-up. Women whose primary tumors have no estrogen receptors fall into a significantly poorer prognostic group than those whose tumors contain estrogen receptors. None of the adjuvant regimens appeared to offer any clear-cut advantage for the estrogen receptor negative patients. Those women whose primary tumor contains estrogen receptors appear to be in a prognostically favorable group, when their treatment regimen included the antiestrogen, tamoxifen. The adjuvant use of BCG immunotherapy does not appear to offer additional benefit, but the follow-up period of these treated patients is too brief to be conclusive. A longer period of observation is needed to determine whether this systemic treatment in estrogen receptor positive patients is preventing recurrence or merely delaying it.