BACKGROUND: Social isolation and loneliness are critical to the health of older adults, but they have not been well-described at the end of life. OBJECTIVES: To determine the prevalence and correlates of social isolation and loneliness among older adults in the last years of life. DESIGN: Nationally-representative, cross-sectional survey. SETTING: Health and Retirement Study, 2006–2016 data. PARTICIPANTS: Adults age >50 interviewed once in the last four years of life (n=3,613). MEASUREMENTS: We defined social isolation using a 15-item scale measuring household contacts, social network interaction, and community engagement, and frequent loneliness using the 3-item UCLA Loneliness Scale. We used multivariable logistic regression to determine their adjusted prevalence by time prior-to-death and by subgroups of interest. RESULTS: Approximately 19% experienced social isolation, 18% loneliness, and 5% both in the last four years of life (correlation=0.11). The adjusted prevalence of social isolation was higher for individuals nearer to death (4 years: 18% vs 0–3 months: 27%, p=0.05) and there was no significant change in loneliness (4 years: 19% vs 0–3 months: 23%, p=0.13). Risk factors for both isolation and loneliness included (p