Mean annual base-flow and stormflow yields of selected water-quality constituents from urban watersheds of Jefferson County, Kentucky, were estimated for 1988-92 to help describe the pro portions of constituent transport from point and nonpoint sources. Yield estimates were based on streamflow and water-quality data collected from a network of 25 stream sites in the county. Water- quality data for which estimates of base-flow and stormflow yields were computed include dissolved oxygen and oxygen demand, dissolved solids, suspended and volatile solids, nutrients, metals, and synthetic organic compounds. Transport of most constituents occurred primarily during stormflow. Chemical oxygen demand was related to the amount of industrial land use in each watershed, nitrite and phosphorus yields were inversely proportional to the amount of nonurban and commercial land use in each watershed, and zinc yields were inversely related to the degree of nonurban land use in each watershed.