We describe a 21 year-old man with an acute development of weakness whose clinical and serial electrophysiological findings were atypical for Guillain-Barré syndrome. Electrophysiological data suggested a diagnosis of "acute motor conduction block neuropathy" (AMCBN). The 6 months of disease duration and the electrophysiological follow-up, which never showed axonal degeneration until complete clinical recovery, raise the issue of the relationship between AMCBN and acute motor axonal neuropathy (AMAN).