The aim of this study was to estimate annual and per-hospitalization cost for firearm injuries by intent, weapon type, and payer source, controlling for patient and hospital characteristics. The data used in this study was from the National Inpatient Sample from 2003 through 2013. The healthcare industry will benefit from information about the annual direct medical costs associated with firearm injuries and the main contributors to these costs, as this information can be used to anticipate costs and to compare to a national benchmark. Information about patient characteristics, injury intent, type of weapon, and payer source will also be helpful, but these relationships have not been examined routinely in previous studies. These data will also be helpful to those planning intervention programs by bringing more attention to the economic burden of firearm injuries in the US.