• Peripheral neuropathy associated with α1-antitrypsin deficiency is an uncommon condition. Several recent studies have investigated the possible roles of serum proteinase inhibitors in inflammatory neuropathies, such as multiple sclerosis, Landry-Guillain-Barré syndrome, and various chronic inflammatory demyelinating peripheral neuropathies. We present a case in which α1-antitrypsin deficiency (proteinase inhibitor ZZ phenotype) was diagnosed in a young white man with clinical signs and symptoms of peripheral neuropathy and a history of Landry-Guillain-Barré syndrome. We wish to emphasize the importance of serum protein electrophoresis in the diagnostic workup of patients presenting with the clinical manifestations of peripheral neuropathy.