OBJECTIVES: To assess the economic burden and health care utilizations of patients diagnosed with post-traumatic stress disorder (PTSD) in the U.S. veteran population. METHODS: Patients diagnosed with PTSD were identified (International Classification of Disease 9th Revision Clinical Modification [ICD-9-CM] diagnosis code 309.81) from the Veterans Health Administration (VHA) dataset from October 01, 2009 through September 30, 2011.  The first diagnosis date was designated as the index date. A comparator group was created by identifying patients without PTSD but with the same age, region, gender and index year, and who were matched by baseline Charlson Comorbidity Index.  A randomly chosen index date served to minimize selection bias. Patients in both groups were required to be at least 18 years old, and have continuous medical and pharmacy benefits 1 year pre- and 1 year post-index date. One-to-one propensity score matching was applied to compare follow-up health care costs and utilizations between patients with and without PTSD. RESULTS: A total of 938,138 patients were identified for the PTSD and comparison cohorts. After 1:1 matching, a total of 333,303 of patients were matched from each group, and baseline characteristics were balanced. Patients diagnosed with PTSD used more health care resources for inpatient (8.57% vs. 2.58%, p<0.01), emergency room (13.45% vs. 7.15%, p<0.01), physician office (99.59% vs. 55.67%, p<0.01), outpatient (99.64% vs. 56.46%, p<0.01), and pharmacy visits (89.97% vs. 56.47%, p<0.01) than patients in the comparator cohort. The PTSD cohort also incurred higher health care costs for inpatient ($2,587 vs. $719, p<0.01), emergency room ($133 vs. $66, p<0.01), physician office ($3,404 vs. $1,254, p<0.01), outpatient ($3,735 vs. $1,430) and pharmacy visits ($629 vs. $362, p<0.01).  CONCLUSIONS: Study results suggest that the economic burden and health care utilizations were significantly higher for patients with PTSD versus those without.