Estimated individual income tax subsidies to agriculture approximate $1 billion annually. The more important provisions of the Internal Revenue Code and regulations that permit tiJC subsidies are described and analyzed. The economic impact of the subsidy plus unmeasured subsidies to corporations are unknown in tenns of resource allocation, price, incomc, supply, and structural cffects. Thc most critical gaps in quantitative effects of tile subsidies in terms of tilC Treasury Department and congressional tax writing committees are highlighted. Needcd research by agricultural economists and possible approaches to such research are suggested in tilis survey article.