Objectives. To quantify the inflation-adjusted costs associated with initial hospitalizations for firearm-related injuries in the United States.Methods. We used the Healthcare Cost and Utilization Project Nationwide Inpatient Sample to identify patients admitted for firearm-related injuries from 2006 to 2014. We converted charges from hospitalization to costs, which we inflation-adjusted to 2014 dollars. We used survey weights to create national estimates.Results. Costs for the initial inpatient hospitalization totaled $6.61 billion. The largest proportion was for patients with governmental insurance coverage, totaling $2.70 billion (40.8%) and was divided between Medicaid ($2.30 billion) and Medicare ($0.40 billion). Self-pay individuals accounted for $1.56 billion (23.6%) in costs.Conclusions. From 2006 to 2014, the cost of initial hospitalizations for firearm-related injuries averaged $734.6 million per year. Medicaid paid one third and self-pay patients one quarter of the financial burden. These figures substantially underestimate true health care costs.