One hundred and seven patients with locally advanced breast cancer were prospectively referred for multimodality treatment on protocol using chemohormonal therapy to maximal response followed by local treatment and maintenance therapy. Forty-eight patients (45%) were diagnosed with Stage IIIA disease, 46 (43%) with Stage IIIB inflammatory cancer, and 13 (12%) with Stage IIIB non-inflammatory disease. Induction therapy consisted of cyclophosphamide, doxorubicin, methotrexate, and 5-fluorouracil with hormonal synchronization using tamoxifen and conjugated estrogens. Local treatment was determined by response to chemotherapy. Patients with a clinical parital response underwent mastectomy followed by local-regional radiotherapy while patients with a clinical complete response were biopsied for pathologic correlation. Those with residual disease received mastectomy followed by radiotherapy while those with a pathologic complete response received radiation only to the intact breast and regional nodes. With a median follow-up of 64 months, patients with IIIA disease had a significantly lower local-regional failure rate compared to IIIB inflammatory patients, with the 5-year actuarial local-regional failure rate as only site of first failure 3% for IIIA disease versus 21% for IIIB inflammatory cancer (p = .02), and local-regional failure as any component of first failure 12% versus 36% (p = .01), respectively. When local-regional failure was analyzed by repeat biopsy, 5/31 (16%) patients with a pathologic complete response treated with radiation only developed a local-regional failure versus 2/53 (4%) with residual disease treated with mastectomy and postoperative radiotherapy. The 5-year actuarial local-regional failure rate as first site of failure was 23% for radiation only versus 5% for mastectomy and post-operative radiotherapy (p = .07). The response to chemotherapy did not reliably predict local-regional control. Both relapse-free survival and overall survival were significantly better for IIIA versus IIIB patients; stratification by repeat biopsy did not however, significantly affect either relapse-free or overall survival.