Objective: The purpose of this study was to identify common and unique risk factors for intimate partner violence (IPV) among young adults in relationships. Guided by two models of IPV, the same set of risk factors was used to examine outcomes of unidirectional (perpetration or victimization) and bidirectional (reciprocal) IPV separately for males and females. Methods: The sample included 10,187 young adults, ages 18-27, from the National Longitudinal Study of Adolescent Health. The respondents were drawn from Wave 3 and stated they had a romantic relationship during the time of the study. The risk factors were primarily related to violent socialization (e.g., childhood maltreatment, youth violence) and personal adjustment (e.g., alcohol use, depression). Results: Approximately 47% of the respondents experienced some form of IPV in romantic relationships, and the majority of respondents reported bidirectional violence. For males, childhood sexual abuse was associated with perpetration and bidirectional IPV, and childhood neglect was associated with bidirectional IPV. For females, childhood neglect was associated with all three IPV outcomes, and childhood physical abuse was associated with bidirectional IPV. Youth violence perpetration during adolescence increased the odds for all IPV outcomes among females, while low self-esteem increased the odds for all IPV outcomes among males. A history of suicide attempts predicted bidirectional IPV across genders. Being married and living with a partner predicted all three IPV outcomes for males and females. Conclusions: The results revealed more common risk factors for bidirectional IPV than unidirectional IPV and few common risk factors across genders. The results indicate that IPV prevention and intervention strategies should be tailored to the unique risk experiences of males and females rather than focus on a common factors approach. However, child abuse, youth violence, and suicide prevention efforts may reduce incidents of later IPV for males and females, and these strategies should continue to be an emphasis in practice and research. (Contains 5 tables.)