OBJECTIVES/GOALS: While most transgender and non-binary (TNB) youth experience improved mental health post-initiating gender-affirming hormones (GAH), some continue to experience persistent, significant depressive symptoms two years post-GAH. Importantly, few studies have examined this issue given the lack of existing longitudinal studies. METHODS/STUDY POPULATION: We aimed to identify intervenable factors predicting persistent clinical depressive symptoms (PD) among TNB youth two years post-initiation of GAH utilizing the Trans Youth Care U.S. Study, an ongoing, multisite, observational study of TNB youth from four major pediatric hospitals across the U.S. We compared TNB youth (ages 12-20 at baseline) with persisting depression symptoms (PD) two-years post-GAH (i.e., PD; N=59) and those youth without (non-PD; n=215). Logistic regression estimated the association between PD and risk (e.g., negative expectations) and protective factors (e.g., parental acceptance, self-efficacy), measured at baseline and longitudinally. A mixed-effects model compared the rate of change of these factors between PD and non-PD youth. Models controlled for birth sex. RESULTS/ANTICIPATED RESULTS: Participants (Mean age=16) identified as transmasculine, then transfeminine, followed by non-binary. PD youth had higher negative expectations at baseline and internalized transphobia by 2-years, while non-PD youth reported greater parental acceptance over 2-years. The odds of PD compared to non-PD decreased with increasing self-efficacy at baseline (OR=0.7, 95% CI:0.5-0.9), whereas negative expectation for the future was associated with increased odds (OR=1.3, 95% CI:0.9,1.8). Moreover, the odds of PD increased 50% with increased rate of change in negative expectations, and odds decreased 50% with increased rate of change in self-efficacy, after adjusting for baseline negative expectations and self-efficacy, respectively. DISCUSSION/SIGNIFICANCE: We identified key intervenable factors for mental health treatment for TNB youth with PD; specifically, negative expectations increased risk for PD while self-efficacy appeared to buffer against PD risk. These findings also support assessment of youth for negative expectations for the future conferring greater risk for later PD.