The Mississippi River Basin Nutrients Science Workshop was a 3-day scientific workshop held October 46, 2005 in St.Louis, Missouri. Its purpose was to assess the state of the science regarding the fate and effect of nutrients (nitrogen and phosphorus) in large rivers in the Mississippi River Basin (including the Mississippi, Missouri, and Ohio Rivers as well as other major tributaries). The Workshop was sponsored by the U.S. Environmental Protection Agency as part of its commitment to supporting States efforts to develop and adopt water quality standards for nutrients in the Mississippi River and its major tributaries. The Workshops mission was to convene scientists from academia, the government, environmental organizations, stakeholders, and policy makers to better understand how excessive nutrients impact large rivers. This would aid the process of developing and adopting appropriate numeric nutrient water quality criteria for these waters.