Military surgical field hospitals are frequently deployed for humanitarian missions. Current Department of Defense doctrine and World Health Organization policy question the appropriateness of their use, because the majority of patients require nonsurgical care. We describe our experiences during the deployment of a mobile army surgical hospital in response to the October 8, 2005, earthquake in Pakistan. More than 20,000 patients received care during a 4-month period. An initially high surgical workload quickly decreased while the volume of primary care patients increased, eventually accounting for 90% of patient visits. Our experience supports deploying primary care-oriented units for humanitarian missions.