Among sexually active adolescent females, obesity is associated with engagement in sexual risk behaviors, particularly with early sexual initiation. However, little research has explored the effect of obesity on the evolution of sexual risk behaviors. We seek to fill this gap by exploring whether timing of sexual initiation predicts associations between sexual risk behaviors and body mass index in early adolescence. Data from the National Longitudinal Survey of Youth 1997 cohort (NLSY97) were used. Females were included if sexual initiation occurred between ages 12 to 25, valid responses were provided to height and weight recorded at round 1, and participants responded to at least 2 of 4 sexual risk behaviors. The primary outcome, sexual risk score, was created based on responses to four sexual behaviors assessed in 1998: number of sexual partners in the past year; lifetime number of sexual partners; proportion of condom-protected sexual acts in the past year; and birth control use. A score of 1 was given to each of these variables which signified “at risk” if they had more than one sexual partner in the past year or ever, had used condoms less than 75% of the time, and were not using a birth control method. Multinomial logistic regression modeling was used to assess the relationship between BMI (independent variable) and sexual risk score (range=0-3) controlling for obesity in early or middle adolescence (ages 12-15 years), age at sexual initiation, race/ethnicity, household parental composition, and socioeconomic status. The sample included 3,474 females. Respondents’ mean age at enrollment was 14.5 years (SD=1.5); 51.8% were non- Hispanic White, 27.2% Black, and 19.9% Hispanic. Early (12-14 years), normative (15-17 years) and delayed (18-25 years) sexual initiators represented 20.4%, 55.2%, and 24.5% of the sample, respectively. The proportion of individuals with a risk score of 0, 1, 2, and 3 was 27.7%, 29.9%, 33.5%, and 9.0% respectively. An interaction was noted between obesity in adolescence and early sexual initiators when the sexual risk score increases from 0 to 1 (p=0.022). Regardless of obesity status, among early sexual initiators the relative risk of having a higher risk score is twice that of normative initiators, and the magnitude of this relationship holds across all risk score transitions (p=0.001; p=0.002; p= 0.037, respectively). Individuals who are obese in adolescence are three times the relative risk to have a risk score of 1 than a score of 0 as compared to individuals who are not obese in adolescence. There are associations between early sexual initiation, obesity and sexual risk-taking behaviors when comparing individuals who have higher risk scores to those with a low risk score.