In the United States, nationally representative civilian studies have shown that BMI is associated with select sociodemographic characteristics. Active-duty military personnel are not included in these surveys and the persistence of these associations in military personnel is unknown. Data from the worldwide, representative 2002 and 2005 Department of Defense (DoD) Surveys of Health-Related Behaviors Among Active Duty Military Personnel were used to assess the prevalence of overweight and obesity and, the association of BMI with sociodemographic characteristics. The final response bases included 12,756 (2002) and 16,146 (2005) personnel. Results indicated that the combined prevalence of overweight and obesity in military personnel increased to an all-time high in 2005 (60.5%) with higher prevalence of obesity in 2005 compared to 2002 (12.9% vs. 8.7, respectively, P ≤ 0.01). Holding other variables constant, regression analysis indicated that women were significantly less likely than men to be overweight or obese in both survey years (P ≤ 0.0001), which is contrary to civilian data. Similar to civilian data, the prevalence of obesity was significantly associated with increased age, black or Hispanic/Latino race/ethnicity, and being married (P ≤ 0.01). US military personnel are not immune to the US obesity epidemic. Demographic characteristics associated with being overweight should be considered when developing military-sponsored weight management programs.