Information on the trophic status of the several basins of Lake Champlain is summarized, the amounts and distribution of total phosphate-phosphorus loading in the lake are evaluated, and recommendations for further study are made. The general objective is to provide basic background information to assist in the development of nutrient control policies for the proper management of the lake. There is a short discussion of the role of phosphorus in the lake ecosystem, how recent thinking is leading to studies of eutrophication models, and a presentation of estimated historical phosphorus loadings. Ongoing studies by various agencies and universities are listed and an extensive bibliography is provided.