BACKGROUND Traumatic brain injury (TBI) is a life-altering condition that has affected many of our soldiers returning from war. In the current conflicts, the improvised explosive device (IED) has greatly increased the potential for soldiers to sustain a TBI. This study's objective was to establish benchmark admission rates for U.S. Army soldiers with TBIs identified during deployment to Iraq and Afghanistan. METHODS The study population consisted of U.S. Army soldiers deployed to Iraq and Afghanistan from September 11, 2001, through September 30, 2007. Population data were merged with admission data to identify hospitalizations during deployment. Using the international Barell Injury Diagnosis Matrix, TBI-related admissions were categorized into Type 1 (the most severe), Type 2, and Type 3 (the least severe). All analyses were performed in 2008. RESULTS Of the 2898 identified TBI inpatient episodes of care, 46% were Type 1, 54% were Type 2, and less than 1% were Type 3. Over 65% of Type 1 injuries resulted from explosions, while almost half of all TBIs were non-battle-related. Overall TBI admission rates were 24.6 for Afghanistan and 41.8 for Iraq per 10,000 soldier-years. TBI hospitalization rates rose over time for both campaigns, although U.S. Army soldiers in Iraq experienced 1.7 times higher rates overall and 2.2 times higher Type 1 admission rates than soldiers in Afghanistan. The TBI-related proportion of all injury hospitalizations showed an ascending trend. CONCLUSIONS Future surveillance of TBI hospitalization rates is needed to evaluate the effectiveness of implementation of preventive measures.