The goals of this study were to examine latent growth in a composite index of sexual risk taking (defined in terms of number of sexual partners and condom nonuse) on five occasions between ages 14-15 and 22-23 years, and to identify associations between latent growth parameters and covariates. As part of the Children of the National Longitudinal Survey of Youth-1979 (CNLSY-79), 740 adolescents provided data at two-year intervals between 1994 and 2004. Latent growth models revealed quadratic growth in youths' sexual risk taking. High initial levels of risk were attributable to early adolescent family structure, the expectation of teenage parenthood, early autonomy from parents, young age at dating initiation, and delinquency. Linear and quadratic growth terms were explained by early adolescent family structure, perceived academic competence, substance use, and delinquency. These associations persisted when time-varying covariates of other contraceptive use and relationship status were modeled.