The emergence of obesity as a distinct disease could have far reaching consequences on an organisation where optimum health and physical fitness are required for soldiers to perform their peace and war roles effectively. This systematic review represents the first to investigate the information relating to correlates, prevention and treatment of obesity in military populations. PURPOSE: To review the empirical evidence concerning the correlates, prevention and treatment of obesity in military populations. METHODS: Through computerised searches of English language studies published between 1990 and May 2009, 595 studies were identified. Visual checks reduced the initial figure to 85. Subsequent filters and data extraction exercises returned a total of 18 papers for review (treatment (13), correlates (4) and prevention (1)). RESULTS: The most successful treatment interventions were observed to contain exercise, healthy eating information, behavioural modification, self-monitoring, relapse prevention, structured follow-up and were supported by trained personnel. Efficacy due to physical activity was underreported, with reductions in body fat (Cohen's d = 0.42 - 0.66) rather than bodyweight (d = 0.14 - 0.38) being the most significant outcome. The major significant correlates (p<0.05) of obesity were enlisted personnel (rather than officers), male, ≥35 years of age, African-American / Hispanic ethnicity, married (with spouse present), and higher level of education. Prevention strategies were poorly reported and focused on a singular intervention surrounding the use of educational booklets and weekly e-mails. CONCLUSIONS: This review highlights the deficit in knowledge concerning treatment, and the lack of engagement in relation to the specific correlates and prevention of obesity in military populations. Although significant, the generalisability and applicability of the findings is questioned due to the focus on the US Armed Forces. Supported by MoD Grant