Two different types of soil contaminated at several levels with unleaded gasoline, diesel fuel, and No. 6 fuel oil were subjected to the toxicity characteristic leaching procedure (TCLP). One soil (Kaw) was sandy-silty, with low organic carbon content (0.6%). The other (Action) was silty-clayey with a higher organic carbon content (2.3%). The TCLP leachates and neat fuels were analyzed by GC/MS for volatile organic analytes. Leaching of the volatile organic contaminants from the Action soil resembled Freundlich-type isotherms, whereas for the Kaw soil, the isotherms were almost linear. This suggests sorption from the gasoline in the Action soil and no retention in the Kaw soil. Diesel- and fuel oil-contaminated soils showed no significant differences in the concentrations of volatiles in the leachates of the two types of soil. The results indicated that there were significant differences in the leaching efficiency of TCLP which depended on soil characteristics and extent of contamination.