Isoxa¯utole is a new pre-emergence corn herbicide which controls both grass and broadleaf weeds. Experiments were performed in the laboratory to study the sorption of isoxa¯utole in ®ve different soils (Moorhead, MN; East Monroe, CO; Ellendale, MN; South Deer®eld, MA; and Chelsea, MI) using the batch equilibration technique. Total initial isoxa¯utole solution concentrations for each soil were 0.05, 0.15, 0.3. 0.8, 1.5, 2.0 and 4.0 mg litre À1 . Analysis of [ring-14 C] isoxa¯utole was performed using liquid scintillation counting, and sorption data were ®tted with the Freundlich model. Isotherms of isoxa¯utole in all the soils were non-linear as depicted by the exponent (n `1.0), indicating differential distribution of sorption site energies in various soils. Since the isotherms were non-linear the data ®t Freundlich's isotherm well, as was indicated by high values of the regression coef®cient (r 2 ). The Freundlich sorption coef®cient ranged from 0.555 to 50.0 (litre n mg lÀn kg À1 ). Multiple regression of the sorption constant, K F against selected soil properties indicated that organic matter content was the best single predictor of isoxa¯utole sorption (r 2 = 0.999) followed by soil pH (r 2 = 0.954). Clay content of the soils did not have a high correlation with K F values (r 2 = 0.453), while the sorption of isoxa¯utole was not in¯uenced by the Ca 2 concentration in the soil solution. Isoxa¯utole sorption increased with an increase in organic matter content of soils. Sorption of isoxa¯utole decreased as the soil pH increased from 4.5 to 8.5, which was depicted by the reduction of K F values. Sorption of isoxa¯utole to the soils varied with differences in binding energies. At a particular net energy value (E*), the corresponding site energy distribution [F(E*)] values followed the order, Chelsea, MI b Moorhead, MN b East Monroe, CO b South Deer®eld, MA b Ellendale, MN. The negative magnitude of Gibbs free energy of sorption (DG x ) indicates the spontaneity of the given sorption process in the soils from Moorhead, MN; East Monroe, CO and Chelsea, MI.