**Abstract**

Sexually transmitted diseases (STDs) disproportionately affect young people, with more than half of the infections occurring in 15- to 25-year-olds, although as an age group they constitute only 25% of the sexually active population. Adolescents have been considered as a key and vulnerable population; adolescents are considered as marginalized populations (i.e., poor access to adequate health services, social and parental acceptance, stigmatization, among others. Every year, 87 million new cases of gonorrhea are reported worldwide in the population from 15 to 49 years old. In 2016, the estimated global prevalence of CT in 15-to 49-year-old women was 3.8% and in men 2.7%, with regional values ranging from 1.5 to 7.0% in women and 1.2 to 4.0% in men. The worldwide prevalence of HSV-2 among 15–49 year old is 11.3% and for HSV-1 among 0–49-year-old is 67%. These numbers alert us about the increase in the frequency of these diseases among young populations; more open sexual behavior could be an important factor for this increase; the treatment of these diseases is challenging due to the difficulties with detection and treatment; in the case of gonorrhea, it could become a major public health problem due to the emerging antimicrobial resistance; in the case of Chlamydia, despite the effective treatment, reinfection is still a possibility and for genital herpes, the disease can be controlled but not cured. This chapter will describe the most important aspects of these three diseases for supporting the clinicians and researchers about the management of sexually transmitted diseases in the adolescent population.

**Keywords:** sexually transmitted diseases, chlamydia, genital herpes, HSV-1, HSV-2, gonorrhea
