Objective This study examined the pharmacokinetics, safety and anti-tumor activity of docetaxel at a dose of 100 mg/m2 in Japanese patients with advanced or recurrent breast cancer. Methods Japanese patients with advanced or recurrent breast cancer received docetaxel at a dose of 100 mg/m2 intravenously every three weeks. The pharmacokinetics were assessed during the first cycle. The patients were allowed to receive supportive care drugs based on the indications and dosages in Japan. Results Six eligible patients aged 39-65 years old and 27 treatment cycles were analyzed. All patients experienced one or more adverse events (AEs). The common AEs were neutropenia, thrombocytopenia, alopecia, rash, diarrhea, neuropathy (sensory), fatigue, nausea, fever, hypoalbuminemia, alanine transaminase (ALT) increased, constipation, and taste alteration. Grade 3 or 4 AEs included neutropenia, leukopenia, anemia, lymphopenia, decreased appetite, γ-glutamyl transpeptidase (GTP) increased, aspartate transaminase (AST) increased, ALT increased, hypertension and cellulitis which were all reversible. There were no cases of febrile neutropenia, serious AEs or deaths. The median number of cycles was six. Dose reductions were not observed and most cycles were administered at their intended doses. No complete response and three partial responses were observed in four assessable patients with evaluable lesions. The maximum concentration and area under the blood concentration-time curve were 3,417.5 ng/mL and 4.35 μg・hr/mL (mean), respectively. Conclusion Docetaxel at a dose of 100 mg/m2 was tolerable with acceptable safety profiles and effective for Japanese patients with advanced or recurrent breast cancer with appropriate supportive therapies, and pharmacokinetic (PK) profiles which corresponded approximately with the findings of previous clinical studies.