Because decisions related to contraceptive behavior are often made by young adults in the context of specific relationships, the relational context likely influences use of contraceptives. Data presented here are from in-person structured interviews with 536 Black, Hispanic, and White young adults from East Los Angeles, California. We collected partner-specific relational and contraceptive data on all sexual partnerships for each individual, on four occasions, over one year. Using three-level multinomial logistic regression models, we examined individual and relationship factors predictive of contraceptive use. Results indicated that both individual and relationship factors predicted contraceptive use, but factors varied by method. Participants reporting greater perceived partner exclusivity and relationship commitment were more likely to use hormonal/long-acting methods only or a less effective method/no method versus condoms only. Those with greater participation in sexual decision making were more likely to use any method over a less effective method/no method and were more likely to use condoms only or dual methods versus a hormonal/long-acting method only. In addition, for women only, those who reported greater relationship commitment were more likely to use hormonal/long-acting methods or a less effective method/no method versus a dual method. In summary, interactive relationship qualities and dynamics (commitment and sexual decision making) significantly predicted contraceptive use.