Most firearm-related injuries are nonfatal and require hospitalization. Using data on 3,257,720 hospitalizations from the National Hospital Discharge Survey (20002010), we determined overall and cause-, gender-, and race-specific trends in firearm-related hospitalization (FRH) and determinants of in-hospital firearm mortality. Types of FRH evaluated, according to International Classification of Diseases, Ninth Revision, Clinical Modification, E-diagnostic codes, were accident (codes E922.0E922.3, E922.8, and E922.9), assault (codes E965.0E965.4), attempted suicide (codes E955.0E955.4), legal intervention (code E970), undetermined intent (codes E985.0E985.3), and war (code E991). A moderate reduction in FRH rates was observed from 2000 to 2011: from 62 FRHs per 100,000 hospitalizations to 57 per 100,000 (P-trend 0.0016). The majority of FRHs were due to assault (P-trend 0.19) or accident (P-trend 0.32) and showed no significant reduction in rates over time, whereas rates for 14 of all FRHsuthose due to attempted suicide (P-trend 0.002) and undetermined intent (P-trend 0.0029)udeclined moderately. Moderate declines were observed among both blacks (from 213.1 FRHs per 100,000 hospitalizations to 164.4 per 100,000; P-trend 0.049) and whites (from 38.4 FRHs per 100,000 hospitalizations to 32.2 per 100,000; P-trend 0.031). The decline was significant only among men (effect size 0.9, P-trend 0.004). In conclusion, the reduction in FRH was driven by a reduction in self-inflicted and undetermined injuries. FRH rates were 6-fold greater among blacks than among whites and 14-fold greater in men than in women throughout the period.