The contribution presents the development of immigration in Slovenia after World WarII from the aspect of influences on the level of birth rate in Slovenia. It analyses immigration to Slovenia and based on a comparison of birth rates of individual ethnic groups in Slovenia defines the role of those in the altogether birth rate in Slovenia. Stress is on comparison of birth rates of the immigrated population and the majority population in Slovenia. It is shown that immigrations did not increase the birth rate but in contrariety with public discourse even lowered it.