The adsorption of selenite by five alluvial soils from the San Joaquin Valley, California, was investigated with respect to the effects of soil composition and pH. Soil samples were prepared in the form of Na‐saturated pastes. Adsorption experiments were carried out in a 50 mol NaCl m−3 background at initial selenite concentrations comparable with those found in natural soil systems. The samples were equilibrated under N2‐stirring in a constant‐temperature apparatus with pH and redox conditions monitored. Selenite adsorption by the soils decreased uniformly with increasing pH in the range 4 to 9 and was independent of soil series above pH 6.