PURPOSE Cyclophosphamide, epirubicin, and fluorouracil (CEF) and doxorubicin and cyclophosphamide (AC) followed by paclitaxel (T) are commonly used adjuvant regimens in women with early breast cancer. In a previous trial in women with locally advanced breast cancer, 3 months of high-dose epirubicin and cyclophosphamide (EC) administered every 2 weeks (dose-dense) was equivalent to 6 months of CEF. We hypothesized that 3 months of paclitaxel after dose-dense EC (EC/T) would be superior to CEF or AC/T. METHODS After lumpectomy or mastectomy, women 60 years of age or younger with axillary node-positive or high-risk node-negative breast cancer were randomly assigned to receive CEF, EC/T, or AC/T for 6 months. This article reports the interim analysis for recurrence-free survival (RFS), which was planned after 227 recurrences. Results A total of 2,104 patients were enrolled. The median follow-up is 30.4 months. Hazard ratios for recurrence are as follows: AC/T versus CEF, 1.49 (95% CI, 1.12 to 1.99), P = .005; AC/T versus EC/T, 1.68 (95% CI, 1.25 to 2.27), P = .0006; and EC/T versus CEF, 0.89 (95% CI, 0.64 to 1.22), P = .46. Three-year RFS rates for CEF, EC/T, and AC/T are 90.1%, 89.5%, and 85.0%, respectively. There was more febrile neutropenia with CEF (22.3%) and EC/T (16.4%) compared with AC/T (4.8%), but more neuropathy with the last two regimens. CONCLUSION Three-weekly AC/T is significantly inferior to CEF or EC/T in terms of RFS. It is too early to detect any difference between CEF and dose-dense EC/T.