BACKGROUND As facial nerve palsy is usually of sudden onset and of obscure etiology, a survey of large series may provide new information. METHODS The files of 40 children suffering from acute facial nerve palsy seen in 3 pediatric and 1 otorhinolaryngologic (ORL) departments between 1980 and 1990 were analysed. Patients with congenital palsy and those with paralysis that appeared after injury or in the course of acute or chronic disease (otitis media, tumor) were excluded from the study. The children were 9 months-16 years old (mean: 7 year 1 month). There were 22 left and 18 right facial nerve palsies. The palsy was moderate in 17 children, severe in 15, and total in 5. Etiologic factors (viral serologic studies, CSF examination), ORL studies and electromyogram of the facial nerve were analyzed in the majority of cases. Corticosteroids were used in 30 patients. RESULTS A viral etiology was suspected and/or confirmed in 13 children; abnormalities were seen in 6 of the patients who underwent lumbar puncture. A familial facial nerve palsy was seen in 1 case and kidney disease in 2 cases. 23 cases appeared to be idiopathic. A moderate permanent residual weakness was seen in only 4 children. The mean time for recovery was 32 days (4-140 days). Corticosteroids did not influence the incidence of complete recovery, but decreased the time for recovery (26 versus 37 days) only in the patients who were treated before the 3rd day of the disease. Patients with idiopathic palsy recovered 23 days before those with viral etiology. CONCLUSIONS Idiopathic and post-viral facial nerve palsies seem to have an excellent prognosis. Corticosteroids seem to have no effect although there is some evidence of benefit when treatment is begun early.