The primary purpose of fitness and body composition standards in the military has always been to select individuals best suited to the physical demands of military service. Obesity has reached epidemic proportions globally, and may have adverse consequences for the military: a worsening prevalence of obesity in young civilian adults could hinder the recruitment and maintenance of military manpower. This review explores the impact of obesity on suitability for employment in defence force careers and any potential impact on long-term occupational health. Studies containing data on obesity and the military were identified from an electronic database. Thirty-eight papers were identified and 17 were included in this review. There is a limited body of evidence available to ascertain whether or not obese individuals are suitable for employment in the military. There are a number of key issues that need to be addressed before a definitive conclusion can be drawn. These include the future health of obese personnel recruited into the military and subsequent implications for health services, costs to the organization and military readiness, and the ability of an obese person to be an active member of the military workforce. Future research should be targeted towards these areas in order to determine the implications of obesity for recruitment and retention of defence force personnel.