Some of the main features of neonatal meningitis, studied in a defined population of infants, are reviewed. The incidence rate was twenty-six cases per 100 000 live-births. The case fatality rate was 43%. Gram-negative intestinal bacilli were the commonest infecting organisms. Streptococci accounted for an important minority of cases. It is stressed that neonatal meningitis usually presents as a non-specific illness, without the clinical signs of meningitis which are familiar in older patients. Twenty-three of the seventy-six infants in this study (30%) weighed 2500 g or less at birth. Another eight infants were born to mothers whose membranes had been ruptured for 24 hr or more.