Several new therapeutic strategies have been introduced for the management of adult traumatic brain injury (TBI) over the last decade, such as the development of management pathways and specialized TBI units and improved treatment of cerebral perfusion. The purpose of this study is to compare TBI-related hospitalization outcomes in the United States between two time periods, 1993-1994 and 2006-2007. We determined the rates of occurrence, in-hospital outcomes, and mean hospital charges for patients hospitalized with adult TBI in 1993-1994 using the nationally representative all-payer Nationwide Inpatient Survey (NIS) database, and compared these outcomes with homologous data from 2006-2007. The incidence of TBI admissions was reduced by 35% in 2006-2007 compared with 1993-1994; (22/100,000 versus 34/100,000 population; p<0.0001). The mean length of hospitalization (mean±SD, in days) was significantly lower in 2006-2007 than in 1993-1994 (2.5±2.4 days versus 2.7±2.6 days; p<0.0001). In-hospital mortality increased significantly in 2006-2007 compared with 1993-1994 (0.8% versus 0.4%, p<0.0001). Average hospitalization charges were significantly higher in 2006-2007 compared with 19993-1994 ($21,460±$21,212 versus $5,142±$4,625; p<0.0001), even after adjusting for inflation. In both time periods, most hospitalized adult TBI patients were graded as mild (98.2% in 1993-1994 versus 98.0% in 2006-2007; p=0.20). There was a significant increase in average hospitalization charges and death rates in all TBI severity subgroups in 2006-2007 compared with 1993-1994. The decline in rate of hospitalization between the two time periods was predominantly related to the decline in the number of admissions of patients with mild TBI. Although the number of TBI admissions was reduced, a significant increase in average hospitalization charges and in-hospital mortality rate was observed in 2006-2007 compared with 1993-1994.