PURPOSE: To compare a full-dose epirubicin-cyclophosphamide (HEC) regimen with classical cyclophosphamide, methotrexate, and fluorouracil (CMF) therapy and with a moderate-dose epirubicin-cyclophosphamide regimen (EC) in the adjuvant therapy of node-positive breast cancer. PATIENTS AND METHODS: Node-positive breast cancer patients who were aged 70 years or younger were randomly allocated to one of the following treatments: CMF for six cycles (oral cyclophosphamide); EC for eight cycles (epirubicin 60 mg/m2, cyclophosphamide 500 mg/m2; day 1 every 3 weeks); and HEC for eight cycles (epirubicin 100 mg/m2, cyclophosphamide 830 mg/m2; day 1 every 3 weeks). RESULTS: Two hundred fifty-five, 267, and 255 eligible patients were treated with CMF, EC, and HEC, respectively. Patient characteristics were well balanced among the three arms. One and three cases of congestive heart failure were reported in the EC and HEC arms, respectively. Three cases of acute myeloid leukemia were reported in the HEC arm. After 4 years of median follow-up, no statistically significant differences were observed between HEC and CMF (event-free survival [EFS]: hazards ratio [HR] = 0.96, 95% confidence interval [CI], 0.70 to 1.31, P = .80; distant-EFS: HR = 0.97, 95% CI, 0.70 to 1.34, P = .87; overall survival [OS]: HR = 0.97, 95% CI, 0.65 to 1.44, P = .87). HEC is more effective than EC (EFS: HR = 0.73, 95% CI, 0.54 to 0.99, P = .04; distant-EFS: HR = 0.75, 95% CI, 0.55 to 1.02, P = .06; OS HR = 0.69, 95% CI, 0.47 to 1.00, P = .05). CONCLUSION: This three-arm study does not show an advantage in favor of an adequately dosed epirubicin-based regimen over classical CMF in the adjuvant therapy of node-positive pre- and postmenopausal women with breast cancer. Moreover, this study confirms that there is a dose-response curve for epirubicin in breast cancer adjuvant therapy.