A 38-year-old woman underwent mastectomy and axillary lymph node dissection for invasive ductal carcinoma with multiple lymph node involvement. The patient received adriamycin 60 mg/m(2) and cyclophosphamide 600 mg/m(2) followed by weekly paclitaxel 80 mg/m(2) (without interruption) as adjuvant treatment. After receiving ten courses of paclitaxel, the patient developed motor neuropathy, with difficulty in ascending stairs and rising from a chair. A nerve conduction study demonstrated impairment of bilateral peroneal nerve function, although the sural sensory nerves were intact. After 2 weeks of withholding paclitaxel treatment, the motor neuropathy was alleviated and the scheduled doses were completed. A pharmacokinetic study of paclitaxel showed the possibility of elimination delay at the last infusion. We suggest that a dose-dense schedule of paclitaxel may be a significant risk factor for this kind of motor neuropathy.