In relation to the apparently low incidence of coronary heart diseases in Arctic populations the fatty acid pattern of muscle and fat tissue of the Arctic seal, birds and mammals were compared with the fatty acid pattern of the corresponding tissues of domestic animals normally used as meat sources in western countries. The triglyceride content of muscle samples was also estimated. A gas chromatography-mass spectrometry system was used for localizing the position of double bonds in the unsaturated acids, by means of their pyrrolidides. The fat tissue from the seal was the main source of polyenoic acids, tri- and pentaenoic acids in the diet of the Arctic hunter. Those acids were derived metabolically from linolenic acid. In contrast polyenoic acids, linoleic acid and its derivatives in the nonarctic diet, were mainly supplied from muscle of nonruminant animals and from sources of vegetable origin. The fat content of muscle tissue in Arctic animals was not less than that of domestic meat.