Meningococcal meningitis, an acute disease characterized by high morbidity and mortality during epidemics, is of considerable public health importance in Ethiopia, Sudan, and other countries in the Sahel. Ethiopia lies within the “meningitis belt” of Sub-Saharan Africa, which extends from Mali across the semiarid Sahel zone south of the Sahara. Epidemics of meningococcal meningitis, caused by group A serotype of Neisseria meningitidis, occur every 8 to 10 years, always during the dry season, and affect up to 1% of the population. Smaller outbreaks occur more frequently. The disease is hyperendemic (about 10 to 50 cases/100,000 population/year) between epidemics. These patterns are not well understood, but herd immunity, climatic factors, especially high temperatures and low humidity which may influence the invasion of the agent through the mucous membranes or enhance its survival in respiratory droplets, poor hygiene, and crowding have been implicated. 1 Numerous epidemics have been documented in West Africa, Sudan, and Ethiopia in the twentieth century. 2 In Ethiopia, meningococcal meningitis was first mentioned in 1901. 3 Outbreaks were reported in 1935, in the 1940s and 1950s, in 1964, 1977, and in 1981 to 1983 and 1988–89. 4 Whereas earlier epidemics are thought to have spread from West Africa to Ethiopia, the 1988–89 epidemic spread with pilgrims returning from Mecca. 1