<p>The globalization era is a development era in all sector, one of them is the rapiddevelopment of<br />themediaandwithin easy reach. In very rapid development give positive and negative impact.The negative<br />impact, arisingfrom the development ofadvancedmediafor teensisgetting easierto find information, especially<br />about sexisconsidered to bea new thingfor teenagers. In can increase premaritalsexrate is<br />increasingeveryyear. This research aims to know the effect of adolescent’s health education about the sex<br />information on premarital sex perception in SMK Nagara district of Kedunggalar Ngawi regency.<br />Research design was Non Eksperimen – one group pre intervensi and post test design. The population was<br />all adolescents in class 10 of SMK Nagara district of Kedunggalar Ngawi regency as many as 200 students<br />and the samples were 133 students. The data collection technique used was Proportional simple random<br />sampling. The independent Variablewas the effect of reproduction health education of adolescent about sex,<br />while the dependent was the premarital sex perception. The instruments used in this research wasa<br />quetionaire, data processing used by Editing, coding,scoring,tabulating,analisa bivariat,univariat and tested<br />by wilcoxon.<br />The result obtained that before being conducted health education the adolescent’s perception on premarital<br />sex was most positive 73 respondents (54,9 %) and after being conducted health education the adolescent’s<br />perception on premarital sex became negative was 86 respondents (64,6%). It was obtained p value 0,002 &lt;<br />0,05so Ho rejected and H1 accepted which means that there is an effect of health education about sex<br />information on premarital sex perception.</p>