The behavior of sulfate concentration in the leachate of an acid podzolic brown earth was studied, when a slug of neutral salt (KCl + KNO3) passed through the upper sulfate-enriched layers of the soil. The effluent of five undisturbed soil columns was collected daily, and H+, Cl-, and SO4– concentrations were measured. A constant flux of water, either 1.0 cm/day or 0.3 cm/day, was maintained. Sulfate concentration in the leachate showed a decrease when the salt passed the columns. The decrease corresponded with an increase of H+ and Cl- concentrations. The behavior of sulfate was almost the same irrespective of the flow rates. At the lower rate, sulfate retention was about twice that at the higher rate. Though precipitation of basic aluminum sulfates cannot be excluded, the behavior of sulfate must be interpreted in terms of specific adsorption.