Nowadays, many teenagers are faced with various challenges related to sexuality, such as the case of adolescent pregnancy enhancement, and high levels of sexually transmitted diseases (IMS) such as HIV/AIDS. This is hard for the teenagers to avoid because of several factors, such as the development of a child who is looking for a personal identity and always wants to try new things in their environment. The purpose of this research is to know the influence of adolescents ' health education through video media to change students ' knowledge of adolescent free sex impact in one of the high schools in Jogyakarta. This type of research is pre-experimented with a research plan of one group Pretests postest. The number of respondents was 97 students using total sampling technique. Bivariate analysis of the statistics of Wilcoxon, with an error rate of 5% (0.05). Most of the knowledge of respondents was pre Test 69 (71.1%), and post Test 61 (92.4%). The average level of knowledge of respondents pre test mean = 77.53 and the knowledge level respondent post test mean = 89.77 with the significance value of knowledge variable 0.000 (P value < 0.05) (α). There is a health education influence through video media to student knowledge about the impact of adolescent free sex age.