Background: Youth’s sexual behaviors have various consequences such as unwanted pregnancy, acquired immunodeficiency syndrome and sexually transmitted infections. Little information is available about the impact of mass media in the development of premarital sexual relationships. This study aimed to explore the role of mass media on premarital sexual relationships among Iranian youth. Methods: This qualitative study was conducted with 26 single boys and girls aged 18-24 years who were living in Isfahan, Iran and have already been started their sexual relationships. Also, 12 other participants who were involved in such an experience were recruited in this study. Data was collected using semi-structured interviews and the observation of youth’s sexual interactions in different fields. Conventional content analysis method was used for data analysis. Results: Three main categories were developed: “foreigner media as the role model”, “the ease of access to sexual contents and materials” and “the ease of interactions and relationships with the opposite sex”. Conclusion: The prominent role of mass media in the formation of premarital sexual relationships was described in this study. This issue needs to be taken into consideration by policy makers for taking necessary actions for reducing the impact of mass media on the youth’s engagement in premarital sexual relationships.