This study investigated the efficacy and tolerability of FEC 100 (epirubicin 100 mg/m2 with 5-fluorouracil 500 mg/m2 and cyclophosphamide 500 mg/m2) every 21 days as neoadjuvant chemotherapy in women with stage I-III primary operable breast cancer. Forty patients were treated with 6 cycles of FEC 100, followed by surgery and radiation therapy. In addition, most patients also received an adjuvant treatment for residual disease (11 chemotherapies and 31 tamoxifen). After 6 cycles of FEC 100, the overall clinical response rate of 75% (CI 95%, 61.6-88.4) was achieved, 22.5% of which were complete responses. Breast conservation was achieved in 70% of patients. A pathologic complete response was confirmed in 6 patients (15%; CI 95%, 3.9-26.1) using Chevallier's classification and in 10 patients (25%; CI 95%, 11.6-38.4) using Sataloff's classification. After a median follow-up of 29.5 months, 3 metastatic relapses were observed. The principal toxicity of FEC 100 was myelosuppression; 51.3% of patients developed grade 3/4 neutropenia. Neoadjuvant FEC 100 was both effective and well tolerated in patients with early-stage operable breast cancer.