We report the first case of axonal Guillain-Barré syndrome (GBS) associated with axonal Charcot-Marie-Tooth disease (CMT). A 30-year-old Japanese man, who had suffered leg atrophy and foot deformity since childhood, developed acute weakness in his four limbs following an upper respiratory tract infection. Nerve conduction studies showed low compound muscle action potential (CMAP) and sensory nerve action potential (SNAP) amplitudes in all the nerves tested. Serial studies showed a rapid increase in CMAP amplitude, but no significant change in SNAP, which indicates that the acute event selectively involved motor axons and was superimposed on a baseline motor-sensory axonal neuropathy, probably CMT Type 2. Elevated serum IgG antibodies against GM1 and GM1b, an increase in CSF protein, and rapid clinical and electrophysiological recovery after plasma exchange support the diagnosis of a pure motor axonal form of GBS, acute motor axonal neuropathy. The association may be coincidental, but a particular susceptibility to axonal damage of CMT2 cannot be excluded.