PURPOSE:The purpose of this study was to describe trends in vaginal intercourse (VI) and condom use during first VI from 2002 to 2017 among never-married 15- to 24-year-olds in the United States. METHODS:Data come from the National Survey of Family Growth. We used logistic regression and Stata's margins package to estimate the percentage reporting VI and condom use at first VI and to conduct statistical comparisons across time. RESULTS:VI was stable for 20- to 24-year-old men, but their condom use increased after 2002. For 15- to 19-year-old men, VI declined after 2011-2015 but condom use increased (83%). Among women, the overall percentage reporting VI and partner's condom use was stable, despite a significant increase in condom use among 15- to 19-year-olds between 2006-2010 and 2011-2015 (69%-75%). CONCLUSIONS:Condom use at first intercourse increased among young men, but a similar pattern was not observed for young women. Understanding why is crucial to the formulation of strategies to increase condom uptake.