Summary In the United States, food insecurity is prevalent in low-income households and is associated with elevated risk of chronic disease, poor health outcomes, and excess avoidable health care utilization and costs. Individuals dually eligible for Medicare and Medicaid are a unique low-income group with significant social challenges, complex health conditions, and higher-than-average health care costs. Interventions to address social determinants of health (SDOH) — such as food insecurity — have the potential to reduce avoidable health care utilization and cost, and the health insurers are increasingly integrating them into care delivery. Using Supplemental Nutrition Assistance Program (SNAP) data from the Pennsylvania Department of Human Services and health care claims data from an integrated health care delivery and finance system, this study reports findings of an innovative collaboration between a health care payer and a nonprofit organization to enroll dual-eligible individuals in SNAP. Data were collected prospectively from 661 SNAP-enrolled individuals and 1,320 individuals in a matched comparison group to explore the effect of SNAP enrollment on health care utilization (inpatient hospitalization, ED visits, and unplanned care) and health care costs (medical, pharmacy, and total cost of care) during the first and second years after SNAP enrollment. Data analysis was designed to answer questions that are important to payer and health care stakeholders, namely, when (i.e., how long after the start of SNAP benefits), how (i.e., what health outcome), and for whom (i.e., what population subgroups) is SNAP enrollment associated with health and cost outcomes. Compared with a propensity score–matched group not enrolled in SNAP, the SNAP enrollees had 16% and 21% lower total health care costs and pharmacy costs, respectively, within the first year postenrollment in SNAP. These group differences remained significant during the second year postenrollment, when SNAP enrollees had 16% and 20% lower total health care costs and pharmacy costs, respectively. Specifically, lower costs were seen among individuals who do not qualify for skilled nursing care. This study contributes to the growing evidence that novel payer-led interventions to address SDOH can influence positive changes in health care utilization and cost reduction, especially among disadvantaged populations.