Concentrated Animal Feeding Operations (CAFO) are large livestock and poultry operations that raise animals in a confined situation. CAFOs can improve the efficiency of animal production but large amounts of manure can degrade air and water quality. The EPA is responsible for regulating CAFOs and requires CAFOs that discharge certain pollutants to obtain a permit. This report discusses: (1) trends in CAFOs over the past 30 years; (2) amounts of waste they generate; (3) findings of key research on CAFOs¿ health and environmental impacts; (4) EPA¿s progress in developing CAFO air emissions protocols; and (5) effect of recent court decisions on EPA¿s regulation of CAFO water pollutants. Includes recommendations. Illustrations.