This study investigated the relationship between mother-adolescent sexual communication and adolescents' engagement of sexual behavior among a sample of 2,669 European American female adolescents, ages 13 to 18 years, and their mothers, from the first Wave of the National Longitudinal Study of Adolescent Health. Communication was assessed by the frequency that mothers discussed the negative consequences of intercourse with their daughters, one year prior to engagement of sexual risk. Additional family factors including mothers' knowledge of adolescent dating, family structure, and socioeconomic status were examined on the effectiveness of sexual communication and pregnancy risk. In addition to maternal influence, this study acknowledged the importance of adolescent predictors on sexual risk, including adolescents' dating experience, decision making, and awareness of the negative consequences of sexual intercourse. This study also determined if decision making/awareness of sexual consequences mediated the relationship between communication and pregnancy risk. Finally, the moderating effects of adolescents' age and mother-daughter closeness were examined in the associations between communication and sexual risk, and between decision making/awareness and sexual risk. Sexual communication influenced engagement of sexual risk. However, contrary to the hypothesis, communication around sexual risk contributed to adolescents' increased engagement of intercourse, and was ineffective in increasing condom use. Regarding adolescent predictors, decision making and awareness of sexual consequences decreased the likelihood of sexual risk, and decision-making partially mediated the relationship between communication and intercourse. There was no moderation of age or mother-daughter relationship quality in the above associations, indicating that mother and adolescent predictors had similar effects for younger and older adolescents, and across groups of mothers/adolescents who reported low and high levels of closeness. These findings suggest that discussing the negative consequences of intercourse does not prevent adolescents' engagement in sexual behavior, and adolescents may interpret this style of communication as controlling and dramatic, and rebel against parents' advice by becoming sexually active. Furthermore, adolescents' cognitive skills and ability to recognize consequences of sex played an important role in deterring sexual engagement. Thus, adolescent predictors may be more of a protective factor against engagement in sexual risk above and beyond that of maternal influence.