The report describes the results of the cooperative study between the USGS and the DEP to determine the concentration and transport rate of PCBs in the Housatonic River. The primary objectives of the study were to determine the concentration of PCBs in water in the river in Connecticut, and to determine the rate that they were being transported downstream. Another objective was to evaluate changes in concentration and transport rate of PCBs that occurred since the previous study conducted in 1979-80 by Frink and others (1982). To meet the objectives, data were collected on streamflow and water samples were collected and analyzed for concentrations of suspended-sediment and PCBs. The study focuses on the Connecticut reach of the Housatonic River in the vicinity of the town of Kent in Litchfield County. The reach was selected because it is an area of prime concern to the fish and invertebrate investigation and had the greatest potential for collecting transport data during storm events. Supplemental data also were collected at several sites on the river located upstream of this reach.