We use data from the Survey of Income and Program Participation (SIPP) to investigate the impact that child Supplemental Security Income (SSI) enrollment has on household outcomes, including poverty, household earnings, and health insurance coverage. The longitudinal nature of the SIPP allows us to control for unobserved, time-invariant differences across households by measuring outcomes in the same household in the months leading up to and immediately following the first reporting of child SSI income. Our regression analyses demonstrate that for every $100 increase in household SSI income, total household income increases by roughly $72, reflecting some modest offset of other transfer income and conditional household earnings. Our analyses further demonstrate that child SSI enrollment is associated with a statistically significant and persistent reduction in the probability that a child lives in poverty of roughly 11 percentage points. Additional analyses suggest that program enrollment has virtually no impact on health insurance coverage because most new SSI recipients have health insurance from Medicaid or another source at the time of enrollment. (author abstract)