BACKGROUND Frequency of rehospitalization and associated resource requirements are unknown for combat casualties. Differences may also exist in readmission rates for injuries to separate body regions. This study investigates rehospitalization of combat casualties with a hypothesis that extremity injuries cause the greatest number of readmissions and require the greatest resources to treat. METHODS A Department of Defense database was queried for hospital admissions of a previously published cohort of service members initially wounded in Iraq and Afghanistan between October 2001 and January 2005. Cohort admission data were collected from October 2001 to February 2008. Body region injured was assigned using International Classification of Diseases Ninth Edition primary diagnosis codes. Resource utilization was calculated using the 2008 Department of Defense billing calculator. RESULTS Our cohort consisted of 1,337 service members with 2,899 admissions. Three hundred forty-one service members had 670 readmissions. Of rehospitalizations, 64% were for extremity injuries making up 66% of all rehospitalization days. Seventy percent of service members injured had at least one admission for extremity injury. Wound debridement made up 12% of all readmissions, and 92% of these were for extremity injuries. The estimated cost of rehospitalization for extremity injuries for this conflict to date is $139 million. CONCLUSIONS Extremity injuries have been shown to result in the greatest long-term disability and require the greatest resource utilization during initial treatment. This study demonstrates that they also are the most frequent cause of rehospitalization and require the greatest resource utilization during rehospitalization.