OBJECTIVES: According to the U.S. Department of Veterans Affairs (VA), roughly 25% of veterans have been diagnosed with diabetes, and the mortality rate averages 5% per year compared to 2.6% in patients without diabetes. The goal of this study was to examine the geographic variation in the annual prevalence of diabetes mellitus (DM) in the U.S. veteran population. METHODS: The study sample was extracted from the Veterans Health Administration (VHA) Medical SAS datasets from 2006 through 2011. All patients diagnosed with DM throughout the study period were identified using International Classification of Diseases 9th Revision Clinical Modification (ICD-9-CM) diagnosis codes 250.xx, 357.2x, 362.0x and 366.41. The change in prevalence over the 6-year period was assessed and the variation in DM prevalence was tested by U.S. state. Statistical analyses were performed using SAS v9.3 software. RESULTS: Puerto Rico had the highest regional prevalence of DM with an increase from 23.79% in 2006 to 26.33% in 2011, while the western region maintained the lowest prevalence throughout the study period (11.34% to 12.85%). The trend in annual state-wide DM prevalence followed an increasing pattern, particularly among southeastern states and Puerto Rico. From 2006 to 2011, the number of states in the DM prevalence range of 15%-20% increased from 6 in 2006 (West Virginia, Nevada, Indiana, Missouri, Rhode Island, Oklahoma) to 25 states in 2011. Alaska and Hawaii were the only states to maintain prevalence below 10% in the 6-year study. CONCLUSIONS: The uneven distribution of DM toward southeastern states suggests a geographic variation in risk areas that may be useful for future targeted intervention strategies.