The purpose of the WHO scientific review on trans fatty acids (TFAs) was to examine the evidence generated since the 1993 Joint FAO/WHO Expert Consultation on Fats and Oils in Human Nutrition, and to inform member countries on the health consequences of TFAs consumption that have emerged since the last report was released. The new information was deemed sufficient to recommend the need to significantly reduce or to virtually eliminate industrially produced TFA from the food supply in agreement with the implementation of the 2004 WHO Global Strategy on Diet, Physical Activity and Health. This goal has been accomplished in some countries and cities, by the virtual elimination of partially hydrogenated vegetable oils in the human food supply, replacing them with healthy cis-unsaturated fatty acids. The document provides the evidence base to promote discussion between the international scientific community related to nutrition and health as well as between agriculturalists, food producers, relevant health professionals, national and international food regulatory agencies, civil society and the private sector to achieve the stated goal. European Journal of Clinical Nutrition (2009) 63, S68-S75; doi:10.1038/ejcn.2009.15