There are an estimated 234,000 cases of measles and 13,851 measles-related deaths per year in Mali. In 1998 and 1999, 548,309 children aged 9-59 months were vaccinated against measles during mass campaigns in urban centers across Mali. After the first campaign, measles incidence decreased by 95% in districts encompassing vaccinated urban centers and by 41% in nonvaccinated districts. There was no shift in the proportion of cases by age group in vaccinated centers. Measles in vaccinated districts after the campaign was likely related to persistent transmission in age groups not targeted for vaccination and among children living in nonvaccinated districts. The second campaign (1999) did not change the incidence of measles in vaccinated compared with nonvaccinated centers. Urban mass measles vaccination probably did not affect overall measles transmission in Mali. Mass vaccination of all children in Mali, targeting a larger age group, will be necessary to reach measles control objectives.Measles kills 1500,000 children !5 years of age each year in Africa [1]. In Mali, routine measles vaccination for children 9 months of age began in 1986 with the Expanded Program on Immunization (EPI). EPI coverage between 1990 and 1999 for children !12 months of age ranged from 35.2% (1992) to 60.3% (1998) according to administrative data. A 1998 independent evaluation of the Malian EPI reported measles vaccine coverage of 23.8% for children !12 months of age. Measles is underreported in Mali because much of the population lacks access to health services and because of incomplete epidemiologic surveillance. The World Health Organization (WHO) therefore estimates that there are actually 230,850 cases and 13,850 measles deaths each year in Mali, assuming a birth cohort of 450,000, vaccine efficacy of 85%, routine coverage of 54%, and a case-fatality rate of 6% [2,3] and that 100% of non-immunized children will be infected.