We examine the health and mortality consequences of receiving Supplemental Security Income (SSI) for older adults. There is robust evidence documenting how social welfare policies that improve economic security like SSI, may also affect health, likely via material gains and psychosocial stress reductions. Consequently, we test whether SSI receipt reduces recipient mortality, including exploratory analysis whether the effects vary across racial groups – if possible. For the proposed study, we take advantage of a prior RCT which included the random assignment to letters which exogenously increased SSI awards and use it as an exogenous leverage to estimate the effects of SSI award on recipient’s mortality in a two-stage estimation procedure. The initial study identified over 4 million SSI potentially-eligible adults 65 or older and randomly sent letters to 10% of them in the final quarter of 2017, informing them of their potential eligibility. In stage one, we limit our analysis of the effects of SSI award on mortality to the study population of the SSA demonstration field. In stage two, we instrument SSI award with the random assignment identifier of the prior field experiment, yielding the local average treatment effect of SSI receipt on mortality. We further use relevant individual-level covariates that are known to affect mortality, such as age or gender, to further improve the precision of our estimates.