Background: According to the 2010 Indonesia Population Census, 26.7% of Indonesia’s population is aged 10 to 24 years; this means that the country has around 64 million youth. The large number in this age group clearly requires serious attention and treatment of all sectors responding to youth’s issues. When young people have little information and knowledge about reproductive health and sexuality, they may not be able to protect themselves from risky behavior. The negative impact upon youth resulting from premarital sexual intercourse may include unwanted pregnancy and illegal abortions that endanger the lives of youth themselves. Methods: This study employed secondary data from the Indonesia Demographic and Health Survey (IDHS) 2012. A total of 10,861 unmarried men and 8,816 unmarried women aged 15 to 24 years old were selected for analysis. Results: Premarital sexual intercourse is found to be more common among unmarried males (12.4%) compared to unmarried females (1.9%) in Indonesia. Age, attitude toward women’s virginity, risky behavior, and having friends that have had sex before marriage are strongest predictors of premarital sexual intercourse among both unmarried males and unmarried females in Indonesia. Education and place of residence, sexuality and reproductive health knowledge, and discussing about sexual matters with friends are also strong predictors of premarital sexual intercourse among unmarried males but not among unmarried females in Indonesia. Conclusions: The study indicates premarital sexual intercourse committed by unmarried youth in Indonesia is affected by personal and environmental factors. The findings also suggest that sexuality and reproductive health education should be provided formally in schools and universities, with more programs focused on university students due to the finding that more older youth (20-24 years) committed premarital sexual intercourse. In addition, family willingness to create open communication is another point that should be taken into account by involving parents and family members to be exposed with Sexuality and Reproductive Health (SRH) information. Therefore, adequate life skill education for youth and family is strongly recommended