Manganese removal is an important problem. Mn cannot be removed by membrane filtration without being oxidized to manganese dioxide, and oxidation is one of the conventional methods for removing man- ganese from water. The aim of this study is to find out the effects of SO^2-₄ (sulphate), NO^¯₃ (nitrate), and humic substances on oxidation of Mn(II) with atmospheric oxygen in drinking water when drinking water obtained from ground water and surface water includes many humic substances, SO^2-₄ and NO^¯₃, due to soil. In this paper we studied the oxidation in four-stage batch systems. First, Mn(II) concentrations used different initial con- centrations, pH values and filter papers having different pore diameters. Then we investigated the effects of SO^2-₄, NO^¯₃, and humic acids following determination of optimum initial concentration, pH and filter paper. According to statistical analysis, there are significant effects of additional substances on Mn(II) oxidation with atmospheric oxygen (p<0.001).