We retrospectively reviewed the clinical files of 45 Guillain-Barré syndrome (GBS) patients admitted to our Department between 1979 and 1989. The age distribution was bimodal with a first peak in young adults (20-40 years), and a second one between 60 to 70 years. Seasonal distribution showed a late fall and a hivernal predominance. Three patients experienced a second attack of GBS 2-9 years after the first one. Thirty-one (69%) presented antecedent events, most often a respiratory tract infection (n = 20) or enteritis (n = 6). Serological studies were systematically performed, including antibody titers against herpes simplex virus, Epstein-Barr virus, cytomegalovirus (CMV), respiratory syncytial virus, human immunodeficiency virus, Mycoplasma pneumoniae, Campylobacter jejuni/coli and cardiolipin. These studies showed the presence of antibodies indicative of a CMV primary infection in 22% cases and of a Campylobacter jejuni/coli infection in 13%. Co-infection was observed in 3 cases. Serology remained negative in 12 patients with a preceding respiratory infection. There was no correlation between serology and the severity of the disease. Absence of antecedent events and of positive anti-infectious serology was observed in only 10 patients.