Adolescence is a period in which a person starts to become sexually mature, forms their gender roles and attitudes about sexual expression. Sexual behavior in this age becomes a part of the normal development of the person. They are suddenly aware of their own sexuality, both in parallel with it form a single identity that strongly affects on person and their own self-image. In today's faster life, children and adolescents are becoming physically and sexually more active, but independence and social maturity will be achieved later. Due to differences at physical and social maturation comes to the earlier start of sexual activity. During the final work, by using the research we presented the results of sexual behavior, risk factors, problems of youth regarding sexuality, modes of education of adolescents about sexual relations, the importance of the impact of health education and activities at the level of primary health care, use of contraception, and the risk factors of having sex. In study we used an anonymous questionnaire with ten open-ended questions. The study included adolescents from one gymnasium and one vocational school from the part of the Varazdin County. According to the results the adolescents at second and fourthgrade vocational school are sexually more active comparing to the adolescents in second and fourth year at gymnasium. In various studies on sexual behavior in the Republic of Croatia has been proven that every year younger people actively involved in sexual relations and all previously described to confirm this behavior. The results of this study were compared to some studies that have been conducted in other parts of Croatia, so we can see if there are differences in the results. In addition to results the more frequent sexual activity of adolescents vocational schools, also the results shown that girls are sexually more active than boys and they are also frequently changing partners. In order to affect at proper healthy development of sexuality and safe sexual life of young people, society needs to continuously work on the education and prevention of adolescent risk behavior. All health care professions are professionals which in fact play an important role at education.