In spite of a measles vaccination coverage of 58%, 33% of 60 infant and child deaths were attributed to measles in a rural area of Kenya in 1988. Among 252 measles cases, there were 20 acute and 5 late deaths which may have been caused by the measles. Median age at infection was 44 months, with 16% of cases below 1 year of age. The highest age-specific attack rates (43% and 41%) were in unvaccinated children 6-11 months and 1-2-year-olds. The overall case fatality rate for children below 5 years was 12.6%, for unvaccinated children below 5, 16.2% and among children below 9 months, 24%. Children in homes with several cases had a higher case fatality ratio than had isolated cases, although not significantly so (RR 1.93, 95% CI 0.71-5.24). The median age of the children who died was 12 months. Overall vaccine efficacy was 62% for children 1-4 years. Our findings suggest that the measles vaccination coverage must be raised considerably in order to reduce mortality rates, and that alternative ways to project infants are needed.