To evaluate the efficacy of docetaxel therapy against anthracycline-resistant breast cancer, twenty patients were treated with docetaxel. Of the 20 patients pretreated with anthracycline, 17 were clinically anthracycline-resistant and the remaining three were refractory to anthracycline on histoculture drug response assay. Nine patients had loco-regional recurrence and 11 had distant +/- loco-regional recurrence. Docetaxel (49-60 mg/m2) was administered every 4 weeks, and was infused 1-13 times (median; 3 times). Of the 19 evaluable patients, eight (42%) showed partial response with the docetaxel therapy. Durations of the response ranged from 1 to 8 months (median; 4 months). Major adverse effects of the therapy were alopecia, neutropenia, and leucocytopenia. Hypersensitivity reaction was observed in one case. In addition, severe adverse effects such as grade 2 pneumonia and grade 4 diarrhea were found in one patient each. In conclusion, although the adverse effects are not negligible, docetaxel therapy is effective against anthracycline-resistant breast cancer.