Androgen Deprivation Therapy (ADT) is the standard treatment for advanced prostate cancer (PCa), although it adversely affects muscle mass, physical function, and quality of life (QOL). It is unknown whether 1) these factors Pre-ADT can predict ADT-induced changes or 2) if non-White, non-Hispanic (NWNH) men experience greater adverse impact on these outcomes than White, non-Hispanic (WNH) men. I hypothesized that 1) greater muscle mass Pre-ADT would be protective against ADT-induced changes in muscle mass, physical function, and QOL and 2) NWNH men would experience worse changes in muscle mass, physical function, and QOL than WNH men. I assessed lean body mass (LBM) [dual energy x-ray absorptiometry], physical function [aerobic capacity (VO2Peak), hand grip strength (HGS), 6-minute walk test (6MWT), stair climb power (SCP)], and QOL [QLQ-C30 questionnaire] in PCa patients (n=59) from the Seattle VA before and 6 months after ADT. I used Pearson correlations to test associations between variables and independent t-tests to compare variables between WNH and NWNH men. Larger LBM (r=0.33, p=0.019, n=50), lower QLQ-C30 Function (r=0.31, p=0.03, n=50), and higher QLQ-C30 Fatigue (r=0.40, p=0.004, n=50) Pre-ADT were correlated with larger 6-month decreases in LBM. NWNH men (n=20) displayed significantly worse Pre-ADT HGS (p=0.038), 6MWT (p=0.037), and SCP (p=0.005) than WNH men (n=39). I anticipate that NWNH men will display worse 6-month changes in LBM, HGS, 6MWT, SCP, and QOL than WNH men in my ongoing analyses. Contrary to my hypothesis, larger LBM Pre-ADT was not protective against muscle loss. Consistent with reports that NWNH men experience greater tumor-related adverse impacts of PCa treatment, worse functional performance Pre-ADT may indicate physical function of these individuals is also disproportionately adversely impacted by ADT. By identifying predictors of adverse ADT outcomes, researchers can develop interventions aimed at preserving muscle mass, physical function, and QOL during ADT for high-risk populations. Additionally, reducing the disproportionate adverse effects of ADT on NWNH men will address disparities within PCa treatment, promoting personalized healthcare optimizing outcomes for all patients.