Samples of serum from 557 patients with a clinical diagnosis of meningitis or encephalitis and referred to the Epsom Public Health Laboratory during a period of 3 years were tested for enterovirus-specific IgM in a mu capture enzyme-linked immunosorbent assay (ELISA). Enterovirus-specific IgM was detected in 45% samples from all age groups. In the 3-5-year age group, 67% specimens were positive. A notable male predominance (73%) was seen in the age group 0-15 years. As predicted, a seasonal increase in incidence was found in the summer and autumn months. Data from a questionnaire sent to the referring laboratories showed only a 5% enterovirus isolation rate from cerebrospinal fluids when isolation of a virus was attempted. The enterovirus IgM ELISA is a sensitive economical and rapid method for use in the diagnosis of viral meningitis.