The population of Charleston County, South Carolina, was studied to determine which segments were at high risk of contracting bacterial meningitis. The incidence of meningitis due to Hemophilus influenzae was highest among blacks living in the poorest areas of the county. The average risk of pneumococcal meningitis was 5.5 times greater for blacks than whites and appeared to be largely independent of income. Neither income nor race significantly affected the risk of meningitis due to Neisseria meningitidis. Two groups were identified as most likely to benefit from effective vaccines: infants in the poorest areas of the county (3.6 cases of H. influenzae meningitis per 1,000 such infants per year) and children under the age of four with sickle-cell disease (9.1 cases of meningitis due to Diplococcus pneumoniae per 1,000 such children per year).