Introduction: Youth experiencing homelessness (YEH) benefit from a variety of services to meet their immediate and long-term needs. Drop-in centers are a popular service venue used by YEH. However, the mechanisms responsible for engaging youth in drop-in services are not clear. The current study uses longitudinal data to explore the role of positive staff relationships in increasing youths’ knowledge and efficacy to access and subsequently use drop-in center services.Methods: 731 youth (Mage= 21.8,SD =2.2, 25.1% female) accessing services at three drop-in centers in Los Angeles, California participated in the study. Surveys were completed at baseline, 1-month, and 3-months later. Path models examined the direct effect of positive relationships with adult staff on service use at the 3-month follow-up, and the indirect effect of service knowledge (assessed at the 1-month follow-up).Results: The direct effect model showed that positive staff relationships at baseline were significantly associated with number of services used at the 3-month follow-up (aIRR = 1.24, 95% CI: 1.00, 1.54). Positive staff relationships were also associated with greater service knowledge at 1-month (b= 0.93,p< 0.001), which in turn was associated with greater service use at 3-months (IRR = 1.15, 95% CI: 1.04, 1.28). The indirect effect of service knowledge was significant (b= 0.13,p= 0.02), suggesting that the association between positive staff relationships and service use was completely mediated by service knowledge.Conclusions: The current study adds to the literature by demonstrating that positive relationships with staff lead to increased service use by increasing youths’ knowledge and efficacy to access services. Efforts should be made to develop positive relationships with YEH in order to engage them in essential services needed to exit homelessness.