U.S. competitiveness with regard to agricultural commodities has been of major interest recently because of the declining U.S. share in world agricultural trade. Competitiveness, defined as the ability of a country to achieve a market share, is determined by a number of factors which affect the excess supply and excess demand conditions of exporters and importers, respectively. On the supply side, this study deals with the costs involved in producing and marketing maize, wheat and soybeans by various middle-income and high-income countries. Private economic costs are used as reported by each country and reflect natural endowments and technology levels as well as specific government policies. Production costs, representing farmer experience over several years, and costs of marketing are adjusted for inflation and converted to dollar equivalents at mid-1986 exchange rates.