Over the past 25 years, farmers have received a decreasing share of the consumer food dollar. Some analysts and farm interest groups are concerned that this decline can be attributed, in part, to increasing concentration in ag. Firms in highly concentrated markets may be able to exert market power by raising retail food prices while also depressing prices farmers receive for ag. commodities. This report provides info. on: (1) trends in concentration for various levels of the food marketing chain in major ag. sectors; (2) trends in retail food expenditures and prices; (3) trends in prices farmers received for major ag. commodities; and (4) the views of experts on the potential effects of concentration on ag. commodity and food prices. Illustrations.