Presenting symptoms, clinical course and paraclinical findings in childhood Guillain-Barré syndrome (GBS) have rarely been investigated prospectively. We performed a multicentre study in GBS diagnosed according to international criteria. Clinical findings were recorded using an ordinal GBS score and additional scores for arm, cranial nerve and vegetative function, and pain. Electrophysiological and CSF investigations followed individual procedures in the local hospitals. Ninety-five children with a median age of 6.2 years were registered over 40 months (53 boys, 42 girls). 70 had suffered an infection and 8 had been vaccinated during the previous 6 weeks. The first symptom was usually a disturbance of gait or neuropathic pain. The symptoms progressed for a median of 7 days. At the height of the disease, 60% of patients were unable to walk and 24% could not use their arms. 46% showed cranial nerve involvement, and 51% autonomous dysfunction. 13% required artificial ventilation. 79% complained of neuropathic pain, half of them to a severe degree. Electrophysiological examination showed demyelination in 74%, and 26% of these presented with very low amplitude compound action potentials. Purely axonal changes were found in 11%. All but eight were treated with i.v. immunoglobulin. Improvement began on day 13 after the first symptom (median). Ability to walk unaided returned after 27 days. In the children observed over the long-term, it took 118 days for them to be free of symptoms. Transient deterioration after immunoglobulin treatment occurred in seven patients, two suffered relapsing GBS, and three developed CIDP. At the end of the observation period (288 days), 75% of patients were free of symptoms. 21% suffered residual symptoms having no effect on daily functioning. The more severely disabled 4% either suffered from CIDP or concurrent myelitis. With this prospective study, the results of earlier retrospective investigations are confirmed. Besides pareses and respiratory compromise, severe neuropathic pain frequently is a therapeutic challenge during the acute phase of the disease. The long-term prognosis is good for most children. However, a change to CIDP and concurrent myelitis can give rise to a worse prognosis.