Background: The percentage of intercourse among university students in Semarang city are increase year by year. The occurred of premarital sex was influence by sexual attitude that representation by 3 components such as label for premarital sexual behavior and rules of applications; evaluation summary about premarital sexual behavior; and supportive knowledge structure toward evaluating process.Objective: The objective of this study was to knowing about the cognitive process of premarital sexual behavior in Semarang. Methode: The explorative study used qualitative approach. There were 10 university students joined in depth interview. · Result: Premarital sexual behavior is still continuing and it's become a latent behavior. It's because of a few causation, such as misinterpretation that premarital sex is a part of reproductive rights fulfillment, sexual harassment in the first experience and sexual satisfaction experience feeling that finally become addictive. Conclusion: interpretation of reproductive rights are not exactly lead to risky sexual behavior.