We report a 13-year-old male patient with Charcot-Marie-Tooth disease (CMT) type 2 who developed severe neuropathy because of vincristine (VCR) for his acute lymphoblastic leukemia. A clumsy gait, muscle weakness in his fingers, and inverted champagne bottlelike muscle in the lower limbs were noticed after remission induction treatment for acute lymphoblastic leukemia, which included VCR at a total dose of 8 mg/m2. An electrophysiologic study showed an almost normal median motor nerve conduction velocity (approximately 50 m/s), markedly reduced M-wave amplitude and sensory disturbance. He was diagnosed as CMT type 2 based on his symptoms and electrophysiologic findings. His symptoms gradually worsened, and even after VCR was discontinued, he could not walk alone for 7 months. VCR has previously been considered to be relatively safe in CMT type 2, however, some patients with CMT type 2 might show severe neurologic toxicities, as seen in patients with CMT type 1.