PURPOSE There is significant public and veteran concerns over the impact of military deployments to Iraq and Afghanistan on veterans' health. This study investigates morbidity among deployers by uniquely comparing after-deployment hospitalizations to before-deployment hospitalizations and hospitalizations among nondeployers. METHODS To compare after-deployment with before-deployment rates of morbidity, we examined active-duty military personnel who deployed for the first time in support of the current conflicts in 2003 or 2004 and had at least 12 months of service before deployment. We also compared the after-deployment hospitalizations to hospitalizations of personnel serving on active duty from May 2002 through May 2004 without a deployment from September 2001 through August 2006. This historical prospective investigation utilized Cox's proportional hazards time-to-event modeling. Hospitalizations for any cause and hospitalizations based on 14 broad diagnostic categories were examined. RESULTS After adjusting for demographic and occupational variables, the after-deployment risk for any-cause hospitalization was greater in comparison with before-deployment (hazard ratio, 1.57; 95% CI, 1.48-1.66) but lower in comparison with nondeployers (HR, 0.95, 95% CI, 0.92-0.98). CONCLUSIONS Active-duty service members have an increased risk of hospitalization after deployment compared with before deployment but a lower risk when compared with nondeployers.