Many countries use trivalent measles-mumps-rubella (MMR) vaccine for their mumps and rubella immunization programs. In Finland, a national 2-dose MMR vaccination program for children, free of charge and on a voluntary basis, was launched in 1982. Serological confirmation of all suspected cases of mumps and rubella has been required since 1987. Despite intensive surveillance, no persistent sequelae or deaths attributable to vaccination have been detected. Indigenous mumps and rubella were eliminated in 1996, but 4 imported cases of mumps and 2 of rubella occurred from 1997 to 1999. Lack of secondary cases indicates sufficient immunity in the community. Compared with an epidemic year, up to thousands of cases of mumps meningoencephalitis and orchitis and around 50 cases of congenital rubella syndrome are now avoided annually. A 2-dose vaccine regimen in children during the last 17 years (1983-1999) has interrupted circulation of the target viruses entirely. Finland is the first country documented to be free of indigenous mumps and rubella (measles was eliminated in 1996). Despite the ongoing possibility of imported disease, major outbreaks probably can be avoided by maintaining high vaccination coverage and the 2-dose policy. JAMA. 2000;284:2643-2647.