While many Asian countries have been challenged by an increasingly high incidence of HIV infection, Sri Lanka has not been among those most impacted to date. However, little is known about sexual behaviors in this country, particularly those of young adults and, as the population of youth grows and becomes more sexually active, there could be implications for the incidence of HIV in this country. Using a two-staged clustered sampling method to achieve a geographically representative sample of young adults in Sri Lanka, data related to sexual behaviors were collected from 3,134 individuals aged 18-20 years. Over half of the males and approximately one-third of the females reported that they were sexually active at the time of the study, with penetrative sexual experiences reported by 20.1% of males and 3.1% of females. Only 26.5% of males and less than 10% of females reported having ever used a condom when participating in vaginal, anal or oral intercourse. The findings of this study suggest that unique partnerships between both governmental and non-governmental entities, both within and outside Sri Lanka and particularly those that involve young adults, may help to maintain this country's low HIV incidence.