The prediction of sexual behaviors in emerging adult population is important because the number of sexually active individuals is high, and many young adults engage in sexually risky behaviors. Attitudes are an effective way to predict behaviors. The attitude–behavior relation is stronger when both attitude and behavior are measured at equivalent levels of specificity. The aim of this study was to provide empirical support of the Attitudes toward Sexual Behaviors Scale (ASBS) predictive capacity for the sexual experience (number of different sexual behaviors performed) as well as to compare it with the Sexual Opinion Survey (SOS; erotophobia–erotophilia dimension) predictive capacity. Participants were 632 heterosexual young adults (57.8% were women) of Spanish nationality aged 18 to 30 years, selected by incidental and snowball sampling. Sociodemographic questions, the ASBS, the SOS, and a checklist about sexual experience were administered online. When the age and sex variables were controlled, the ASBS predictive capacity for the sexual experience was found to be greater than the SOS predictive capacity in both young men and women. These results might be explained by the higher correspondence in the sexual experience measure (specific sexual behaviors) with the ASBS than with the SOS.