Abstract: The application of new knowledge in food science and nutrition is important in ensuring that Service members are in peak physical and mental condition for warfighting. The Defence Nutrition Research Centre of the Australian Defence Science and Technology Organisation has conducted extensive research and development to determine the nutritional requirements of Australian Defence Force occupations. In this paper, three aspects of this research are discussed. Determining and Satisfying Nutritional Requirements: Mean daily energy expenditure of Australian Defence Force (ADF) members varied from 12 MJ (sedentary occupations) to 28 MJ (Special Forces selection) per man. New ration scales and ration packs have been devised to satisfy demonstrated nutritional needs. Hydration Requirements: Sweat rates of 1.0-1.5 L/h were found during infantry operations in hot/wet and hot/dry environments. An investigation of the value of a new system of water carriage and delivery in encouraging water intake found significant benefits, and no decrements associated with the new system. Ergogenic Aids: Some substances and techniques that enhance athletic performance (ergogenic aids) show potential as aids to military performance. International co-operative and collaborative RD is continuing on the safe and effective use of ergogenic aids in the military context.