Introduction: sexually transmitted diseases are communicable pathologies caused by microorganisms such as viruses, fungi and bacteria, which are acquired through sexual or non-sexual contact. Objective: to determine the knowledge and attitudes of adolescents towards sexually transmitted diseases. Methods: a quantitative, non-experimental, cross-sectional cohort study was carried out with a population made up of 102 leveling students of the Nursing Career. Using two validated instruments, with a Cronbach’s alpha of 0,88 and 0,66, the first consists of 24 multiple-choice questions that evaluate five components: general knowledge of HIV, knowledge of condoms as a protective method, knowledge of HIV transmission routes HIV prevention and knowledge about other sexually transmitted diseases and the second consisted of 10 questions; 8 open and 2 closed to know their attitudes. Results: the participants comprised an age between 15 to 19 years; with a predominance of the female gender in 82,4 %, there are adolescents who have not started their sexual activity with 43,1 %. In addition, this research aims to know the knowledge, so the results of the evaluation indicate that most adolescents have an average knowledge (15 points) on this topic. Conclusion: it can be concluded that adolescents have an average knowledge regarding STIs, which is why it is essential to promote health promotion and disease prevention as a fundamental nursing strategy.