The intake of trans octadecenoic acids is estimated by a national consumption assay. The daily intake in West Germany differs between 3.4 g for women and 4.1 g for men. The consumption of trans fatty acids decreased in the last years, due to the progress in food technology and changes in nutritional habits. The main sources of trans fatty acids are partially hydrogenated vegetable fats just as well as ruminant and dairy fats.