The Guillain-Barré syndrome (GBS) is characterized by the acute onset of rapidly progressive, symmetric muscle weakness with absent or decreased muscle stretch reflexes. GBS is the most common cause of acute flaccid paralysis in childhood, with an incidence in Australia of 0.8 per 100,000 children per year. Recent advances in this field have included identification of a number of clinical and neurophysiologic subtypes of GBS, enabling improved characterization of etiology and improved prognostication in this disorder.