During the months of March through September 1972, a biological survey was conducted on the effects of a 7,000-gallon diesel fuel spill into Boone Creek, a small stream near Salem, South Carolina. Boone Creek empties into Lake Keowee, an impoundment on the Keowee River. Macroinvertebrate organisms, periphyton, and fish were collected, preserved, identified, and enumerated. Sediment samples were taken for hydrocarbon analysis. Oil was observed in the creek during the entire six-month study period. Locations downstream from the oil spill generally contained reduced numbers and types of organisms. An estimated 90% of the fish community was killed during the initial oil spill. Periphyton growths, dominated by diatoms, increased at locations downstream from the oil spill during May and June. Analysis of substrate sediment samples revealed hydrocarbons still present in Boone Creek and Lake Keowee 13 months after the spill occurred.