The objective of the study was (i) to compare the nutritional composition of milk produced in organic and conventional production systems taking into consideration: different proportions of grass or grass silage, maize silage and different amount of concentrate (cereals), and (ii) to define the variation in content of pro- and antioxidants in milk in relation to regional variation, feeding and season. The feeding regime from 25 farms from Denmark, 20 farms from Sweden and 25 farms from United Kingdom was reg-istered and milk samples were collected and analysed for the content of antioxidants and fatty acid compo-sition. The daily milk production was significantly higher in the conventional milk production systems in the two Scandinavian countries compared with the United Kingdom. Milk from the conventional low input production system in United Kingdom has signifi-cantly higher amount of fatty acids and antioxidants derived from the high amount of pasture in the diet, where in contrast the conventional production sys-tems in Denmark and Sweden had significantly higher content of fatty acids derived from maize silage. The data overall indicated differences between the milk composition as a consequence of the feeding compo-sition in different systems and countries.