Current scientific studies performed all over the world will probably eventually lead to the production of a vaccine against measles that will be safe, acceptable, and effective. A voluntary mass vaccination against measles will be unlikely. Public Health authorities can hardly support financially or be willing to undertake or to push the introduction of this immunization in such public drives as we have seen in vaccination against poliomyelitis, the propaganda for such vaccination was successful. The disease attacks both children and adults, and is a far greater threat against the lives and health of people than measles. It was therefore far more easy to persuade the populations to give their consent to mass vaccination. In socio-economically developed countries measles is a rather benign disease, and it is therefore more difficult to persuade parents of the necessity of the vaccination. Measles vaccination will be a matter of decision of the individual physician attending child welfare centers and institutions for children. In developing countries measles is a more serious disease, but mass vaccination of the whole population will not be possible, even with international financial support, due to lack of sufficient health personnel, to the size of the population and to local geographical conditions. In selected groups of the population all over the world the vaccination against measles will play an important role in the future. An effective and safe measles vaccine is to be regarded as a great benefit to mankind and will certainly save many thousands of children's lives.