For only eight decades (from 1921 to 2002), the population of Vojvodina got older for even ten years, which represents a great problem for the future of the population in this region. In the world, the average age of the population at the beginning of the 21st century is 27,6 years, showing that it is younger than the population in Vojvodina was at the beginning of the third decade of the 20th century. However, all population in Vojvodina does not get old at the same speed. Observing specific ethnic groups, the authors of this paper established differences related to the average age. There is a conclusion that the youngest population is the one which also has greater birthrates, and that is the case with the Goranci and the Roma. In addition to birthrate, the average age is also influenced by the number of the population itself, so the greater average age appears in these ethnic groups which are less numerous. On the basis of the spread of some ethnic groups in Vojvodina, the paper also established the difference in the average age of the population related to some regional units.