Thirty-four patients were identified with Guillain-Barré syndrome (GBS) on review of 266 neuropathy cases admitted to a Copenhagen county hospital from June 1977 to January 1984. The age-adjusted incidence rate of GBS is 2.0 x 10(-5) years-1. The natural history of the disease, antecedent events, symptoms and signs, autonomic dysfunction, sequelae, CSF findings and mortality are described. Six cancer patients with GBS differed significantly from the non-cancer patients in a more protracted disease course and failure to improve. The National Institute of Neurological and Communicative Disorders and Stroke (NINCDS) criteria for the diagnosis of GBS are discussed, and it is concluded that the criteria, although useful in comparative studies, are too restrictive when used in clinical practice.