Objectives: The aim of this study is to show the attitudes and knowledge of Vinkovci adolescents about sexually transmitted diseases, and whether there is a difference in knowledge in relation to gender, age, school achievement and the school they attend. Methods: A cross-sectional study was conducted. The study was conducted on the population of adolescents in the area of Vinkovci. 101 adolescents aged 15 to 19 years were included. The respondents filled in a ten-minute anonymous survey questionnaire online, in the period from March 1st, 2021 to July 1st, 2021. Results: Of the total number of respondents, the largest number aged 16 to 18, attends technical school and passes with very good results. Of the total number of respondents, 33.7% of respondents had sexual intercourse and are sexually active. Adolescents from the Vinkovci area show a relatively good but insufficient level of knowledge about sexual health and sexually transmitted diseases. The survey revealed significant differences in the attitudes and knowledge of Vinkovci adolescents, in a way that a significant difference was observed in the level of knowledge regarding the type of school they attend, i.e. significantly higher knowledge is shown by Gymnasium students compared to Technical high school students. Conclusion: Education about sexually transmitted diseases in adolescence is extremely important. The task of the nurse is systematic, complete and continuous observation, which includes the condition, appearance and behavior of the patient. Through prevention and communication measures, it is necessary to ensure a positive and open approach to sexuality, encourage preventive examinations, give support and appropriate treatment. It is necessary to provide education and counseling and open access to information on sexuality in order to raise the level of knowledge of adolescents about sexually transmitted diseases.