Neisseria meningitidis is an important cause of serious bacterial infections in children. We undertook a study to identify meningococcal infections of the blood, cerebrospinal fluid, or both of children in a defined geographic area to describe the burden of disease and the spectrum of illness. We reviewed the medical records of all children aged <18 years who had meningococcal infections at the 4 pediatric referral hospitals in Boston, Massachusetts, from 1981 through 1996. We identified 231 patients with meningococcal disease; of these 231 patients, 194 (84%) had overt disease and 37 (16%) had unsuspected disease. Clinical manifestations included meningitis in 150 patients, hypotension in 26, and purpura in 17. Sixteen patients (7%) died. Although meningococcal disease is devastating to a small number of children, we found that the burden of pediatric disease that it caused at the 4 pediatric referral centers in this geographic region was limited; that patients with overt meningococcal disease are most likely to have meningitis; and that individual practitioners are unlikely to encounter a patient with unsuspected meningococcal disease.