This summary will present an overview of results for the annual limnology program for the Great Lakes which began in 1983. The limnology program provides information on key environmental factors that influence the food chain and fish of the Great Lakes. The annual monitoring of the Great Lakes began in 1983 for Lakes Michigan, Huron, and Erie; in 1986 in Lake Ontario; and in 1992 for Lake Superior. The sampling strategy is to collect water and biota samples at specific water depths from a limited number of locations in each lake twice every year.