Background: ALL is a rare disease with markedly poor prognosis in older adults. As large population-based mortality data are limited, we described the risk of death among older adults diagnosed with ALL. Methods: Using 100% Medicare ALL data, 2007-2012, we identified patients ages ≥ 66 years newly diagnosed with ALL in 2008-2011 and continuously enrolled in Medicare fee-for-service (FFS) for 12 months prior to ALL index date (baseline period). Presence of ALL was defined as 1 inpatient (IP) or 2 outpatient (OP) claims on different dates in any 2-month interval carrying an ALL code. The index date was defined as the earlier date of the 1^st IP or the 2^nd OP code. Baseline comorbidity level was defined using a modified Charlson Comorbidity Index. Follow-up (F/U) began on the index date and ended at the earliest of death, disenrollment from FFS, 3 years, or December 31, 2012. Unadjusted cumulative probability (CP; 95% CI) of death was estimated using the Kaplan-Meier method; the log-rank test was used to compare the CP of death by patient characteristics. Results: The cohort included 1843 patients (mean [SD] age: 78.7 [7.8] years; 53% female; 88% white). Comorbidity level was low, medium, and high for 52%, 30%, and 18% of patients, respectively. During the mean (SD) 12.8 (13.1) months of F/U, 1280 patients (70%) died. The CP (95% CI; %) of death was 21.5 (19.7-23.5) at 30-days, 46.5 (44.2-48.8) at 6 months, 57.4 (55.2-59.7) at 1 year, and 72.9 (70.7-75.1) at 3 years overall, and significantly higher for those diagnosed at older ages and with greater comorbidity (Table; P< 0.001). Conclusions: Risk of death significantly increased with advancing age and comorbidity level in elderly patients newly diagnosed with ALL. Given the high risk observed for early death, further analyses are warranted to understand the real-world management of ALL in older adults.