Adolescence signifies the arrival of sexual identity, they need information and support and guidance about sex. The progress of science and technology has a negative impact on the lives of adolescent sexual behavior. The technique used in this study is a type of quantitative analytic with cross sectional survey. The purpose of this study was to determine the relationship of electronic media exposure to sexual behavior in SMAN 5 Mandau in 2015. The type of research instrument was using the cheecklist format. The population of this study were students of SMAN 5 Mandau in 2015 in class XI totaling 229 people, the technique used in sampling used a simple random random sampling of 146 people. The analysis of this study is bivariate conducted by the chi squere test, the data is processed using a computer with the SPSS program. From the results of the study it was found that the majority of students were heavily exposed because of television media as much as 85.6% (125 people). And the majority of the media exposed to mild media as much as 82.9% (121 people). As well as the majority who experienced mild exposure by internet media as much as 84.2% (123 people). And the majority of sexual behavior that is not deviating is 54.1% (79 people). Based on the relationship of electronic media exposure to sexual behavior at SMAN 5 Mandau obtained X2 count (9,717)> X2 table (3,481) this indicates a relationship between electronic media exposure to sexual behavior at SMAN 5 Mandau 2015. Advice for health workers to be used as material input in anticipating changes in adolescent sexual behavior towards deviating due to exposure to electronic media.