BACKGROUND: the percentage of HIV infections in the age group 20-24 years (14%) and the highest percentage of cumulative AIDS cases un the ge group 20-29 years (30.7%), then in the age group 15-19 years (3.3%). The incidence in school childen or students as much as 1086 people and HIV / AIDS among adolescents aged 15-29 years. the prevalence of AIDS cases per 100.000 population by province was ranked 19th out of 33 provinces in Indonesia, where there is a prevalence of 9.33 cases of AIDS. There data indicate that young age, 15-29 yeas old are the most vulnerable population and need to be target in HIV / AIDS in Indonesia. Methods: This study is a Pre experiments with One Group Pretest Posttest Design. The simple of this study uses total sampling, all students of class XI SMA Negeri 1 Selupu Rejang as much as 167 people. collecting data from primary data obtained directly by Administering the object, through a questinnaire. To test the results of studies using non-paramentric statistical Wilcoxon test with a level of 0.05. Result: Showed differences in the mean value oof the students knowledge about HIV/ AIDS before and after the health education with a p value of 0.000. This Means that health education on HIV/AIDS affect knowledge of students. Conclusion: health education about HIV/AIDS may increase adolescent knowledge about HIV/AIDS.