Two hundred seventy-three sediment samples were collected from 63 Illinois lakes in summer 1979. These samples were analyzed for percent volatile solids, chemical oxygen demand (COD), nutrients, heavy metals and organochlorine compounds. When contrasted to other studies, Illinois lake sediments were relatively low in total Kjeldahl nitrogen, chemical oxygen demand and percent volatile solids. Most lakes exhibited fairly low metal concentrations. Organochlorine compounds rarely exceeded detection limits. A classification of Illinois lake sediments based on statewide mean concentrations was prepared. An attempt was made to correlate fish flesh concentrations with sediment concentrations. No simple linear relationships were discerned.