Teenage pregnancy is a worldwide medical and social issue, associated with many physical, psychological and social consequences and can result in birth, miscarriage or abortion. Aim: The aim of the present study is to find those risk factors that contribute to teenage pregnancy. Results: In U.S.A., according to data from Unicef, the birth rate among teenagers touches the 52.1% and it is four times higher, than the corresponding rate recorded in the countries of Western Europe. The United Kingdom has the highest rate of teenage pregnancy in Europe and in contrast to the decline in the rate of teenage pregnancy, recorded in the remaining countries of Western Europe, this figure has remained relatively stable, especially in adolescents aged 16 years and below. In Greece, according to National Statistics Office, in 2007, we had 3.129 births by teenagers under 18, with 75 births by teenagers under 15. The main factors contributing to the incidence of teenage pregnancy are socioeconomic factors, the family, the education and the sexual behavior of teenagers. Conclusions.It is necessary the state, through the health services and the education programs, to provide modern sex education in schools, as well as programs of prevention and health education in primary health care. The cooperation of these authorities is essential, to better address the extent and consequences of teenage pregnancy.