To determine whether capecitabine schedule adaptation improves the tolerability of capecitabine-paclitaxel combination therapy for metastatic breast cancer (MBC), patients with anthracycline-pretreated HER2-negative MBC were randomized to either arm A (21-day cycles: capecitabine 1,000 mg/m(2) twice daily, days 1-14; paclitaxel 60 mg/m(2), days 1, 8, and 15) or arm B (28-day cycles: capecitabine 1,000 mg/m(2) twice daily, days 1-5, 8-12, and 15-19; paclitaxel 80 mg/m(2), days 1, 8, and 15). The primary endpoint was the incidence of dose reductions or delays >1 week for grade 3/4 toxicity. Secondary endpoints were efficacy and safety. All 130 randomized patients were evaluable for safety. Dose reduction or delay for grade 3/4 toxicity occurred in 39% of patients in arm A and 34% in arm B during cycles 1-6. In arm A, there were significantly more toxicity-related dose reductions (cycles 1-6: 82 vs. 67%, respectively; P = 0.05) and discontinuations (29 vs. 8%, respectively). Grade 3 diarrhea occurred in 12 and 0%, respectively, and grade 3 hand-foot syndrome in 12 versus 9%, respectively (grade 4 not applicable). There were no detectable differences in efficacy. Weekday capecitabine dosing with weekly paclitaxel may improve tolerability without a detrimental effect on efficacy, and merits further evaluation in patients suited to combination chemotherapy.