The experiments reported in this paper were conducted at a pilot plant consisting of filtration columns filled with oxidative filter materials. The installation was supplied with water containing manganese in concentrations ranging from 0.2 to 1.4 mg/L. The aim of the experiments was to determine the effectiveness of manganese removal on the three filter media as a function of their internal structure parameters (volume and pore surface area) and MnO2 content. To interpret the results, the authors introduce a new parameter: catalytic activity coefficient, the product of the parameters mentioned above. This coefficient predicts the extent of manganese removal in a filtration process using an oxidative filter material. The coefficient may be the basis for a general classification suitable for all kinds of oxidative filter materials.