In this study, levels and sources of omega-3 fatty acids (FA) available for consumption in the US food supply, dating from 1935, are estimated. omega-3 FA assessed are eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), and linolenic acid (LNA). Estimates are based on annual per capita food use data and data on the omega-3 FA content of foods. Although fish use increased, the EPA level was slightly lower in 1985 than in 1935-1939, reflecting a marked decline in use of certain fatty fish. The level of DHA increased, due to greater use of poultry. The level of LNA increased because of greater use of soybean oil. These estimates are currently the only source of data on omega-3 FA in the American diet.