A comparison of the epidemiology of community-acquired bacterial meningitis between Jewish and Bedouin populations cohabiting one geographical area is reported here. During the years 1981 to 1985, 100 children younger than 13 years old with community-acquired bacterial meningitis were hospitalized. Seventy-one patients were younger than 12 months. The principal bacteria isolated were Haemophilus influenzae 42% Streptococcus pneumoniae 29% and Neisseria meningitidis 20%. The case fatality rate was 12%. The chance of acquiring meningitis during the first 5 years of life was twice as common among Bedouins than among Jews (328/100 000 vs. 173/100 000, respectively; P < 0.0001). The most common cause of meningitis during the first year of life was S. pneumoniae among Bedouins and H. influenzae among Jews. Meningitis caused by H. influenzae and S. pneumoniae was usually associated with respiratory morbidity during fall and winter among Jews, but with diarrheal morbidity during summer and fall among Bedouins. Since the most prevalent type of morbidity among Jews results from respiratory infections and among Bedouins from diarrhea, our findings suggest that community-acquired bacterial meningitis is associated with the type of morbidity most prevalent in the community at any given season rather than with a specific type of infection.