The proportion of one-year-old children immunized against measles is the proportion of children aged one who received one dose of measles vaccine. A child is considered adequately immunized against measles after receiving one dose of vaccine. Immunization is an essential component for reducing under-five mortality, and it serves as a proxy to measure the coverage and the quality of the child health care system. This indicator is also related to the fourth MDG aiming at reducing child mortality.