The fatty acid composition of several oilseeds has been modified to solve technological oil problems and to adapt them to the requirements of the food industry. The end goal is to have tailor-made oils and fats. For example, the two main oil crops, soybean and rapeseed, contain around 8-10% linolenic acid in their oils making them very easily oxidised. New lines with reduced amounts of this fatty acid have been obtained to solve this problem. In general an increase on oleic acid is desirable to make oils more stable at the high temperatures occurring during frying or baking. The most important modification for the margarine and shortening industries would be to increase the amount of saturated fatty acids, palmitic or stearic, so that the hydrogenation process and else the trans fatty acids can be avoided. In this case it is better to increase the amount of stearic acid instead of that of palmitic acid because stearic acid does not raise the cholesterol levels. New plant varieties should also produce fats with the plasticity needed for margarine. Plant varieties with these modifications have been selected in sunflower, soybean and rapeseed. This paper reviews the current situation of the modified oil crops.