The inflammatory demyelinating neuropathies constitute a significant proportion of the acquired polyneuropathies. Major progress in finding the causes and in the treatment of these neuropathies has been made over the last decade. Early recognition is of paramount importance, because timely and appropriate treatment can largely reduce morbidity and disability. Electrodiagnosis plays a key role in the detection and characterization of the inflammatory demyelinating neuropathies. Electrodiagnostic criteria for primary demyelination have therefore been developed. They are empirically based on changes of nerve conduction parameters in populations of patients with a confirmed clinical and laboratory diagnosis of inflammatory demyelinating neuropathy. The challenge consists of defining criteria sets that are highly specific but also as sensitive as possible. Most of the hereditary demyelinating neuropathies are part of Charcot-Marie-Tooth disease type 1. The pattern of nerve conduction abnormalities usually provides valuable clues for the distinction from chronic inflammatory demyelinating neuropathies.