Results. For doxorubicin and vinorelbine, the objective response rate was 55% (95% confidence interval [CI]: 42% to 68%), median time to disease progression was 34 weeks, median time to treatment failure was 32 weeks, and median survival was 92 weeks (95% CI: 72 to 128 weeks). For fluorouracil and vinorelbine, the objective response rate was 45% (95% CI: 31% to 59%), median time to disease progression was 32 weeks, median time to treatment failure was 30 weeks, and median survival was 53 weeks (95% CI: 47 to 64 weeks). The most common adverse event was grade 3 or 4 granulocytopenia, which occurred in 95% of subjects in the doxorubicin-vinorelbine group and in 88% of those in the fluorouracilvinorelbine group. The most common nonhematologic adverse event was grade 3 or 4 stomatitis, which occurred in 9% and 32% of subjects in the two groups, respectively.Conclusion. Both vinorelbine-containing regimens appear to offer useful options as initial therapy for advanced breast cancer. Both regimens were active, and any efficacy differences between the two may have been related to differences in prognosis for the anthracyclinepretreated group (i.e., selection for prior aggressive adjuvant therapy) and or comorbid cardiac conditions. Both regimens were associated with predictable but manageable toxicity, but a lower dose of fluorouracil (e.g., 600 mg/m 2 /day) should be used to reduce the risk of stomatitis.