ABSTRACT: To determine to what extent demographic, social support, socioeconomic, geographic, medical, and End-of-Life (EOL) planning factors explain racial and ethnic variation in Medicare spending during the last 6 months of life.Retrospective cohort study.Health and Retirement Study (HRS).Decedents who participated in HRS between 1998 and 2012 and previously consented to survey linkage with Medicare claims (N = 7,105).Total Medicare expenditures in the last 180 days of life according to race and ethnicity, controlling for demographic factors, social supports, geography, illness burden, and EOL planning factors, including presence of advance directives, discussion of EOL treatment preferences, and whether death had been expected.The analysis included 5,548 (78.1%) non-Hispanic white, 1,030 (14.5%) non-Hispanic black, and 331 (4.7%) Hispanic adults and 196 (2.8%) adults of other race or ethnicity. Unadjusted results suggest that average EOL Medicare expenditures were $13,522 (35%, P < .001) more for black decedents and $16,341 (42%, P < .001) more for Hispanics than for whites. Controlling for demographic, socioeconomic, geographic, medical, and EOL-specific factors, the Medicare expenditure difference between groups fell to $8,047 (22%, P < .001) more for black and $6,855 (19%, P < .001) more for Hispanic decedents than expenditures for non-Hispanic whites. The expenditure differences between groups remained statistically significant in all models.Individuals-level factors, including EOL planning factors do not fully explain racial and ethnic differences in Medicare spending in the last 6 months of life. Future research should focus on broader systemic, organizational, and provider-level factors to explain these differences.