Between 1973 and 1981, 223 patients were seen at hôpital Sainte-Justine in Montreal for enteroviral infection of the nervous system. In 161 the cause was documented by isolation of an enterovirus from the cerebrospinal fluid (CSF). The viruses most frequently isolated were echovirus 11 (36 isolates), echovirus 30 (24), coxsackievirus B2 (23), coxsackievirus B3 (19), echovirus 6 (18), coxsackievirus B5 (16), coxsackievirus A9 (15), echovirus 9 (13), echovirus 7 (12) and coxsackievirus B1 (11). Aseptic meningitis was diagnosed in 200 cases and encephalitis in 12. The remaining 11 patients presented with the features of septicemia or with convulsions. In 33 patients an enterovirus was isolated from the CSF in the absence of pleocytosis. Polymorphonuclear cell predominance was noted in the initial CSF sample in 95 cases; it was persistent in 11. There were five mixed infections; in three cases two viruses were isolated from the same CSF sample. Two patients died: one, a child with hypogammaglobulinemia, had fatal polioencephalitis; the other, a 6-month-old infant brought to the emergency room in unexplained cardiopulmonary arrest, had echovirus 6 meningitis. Of the 172 patients admitted to hospital 96 received parenteral antibiotic therapy. The impact of enteroviral infections of the central nervous system on hospital resources could be substantially reduced if a rapid, sensitive and specific laboratory method of diagnosing these infections were available.