Abstract: A filter sheet which is free of asbestos, and which contains cellulose, filtering aids such as diatomite, perlite, etc., and cationically modified material in the form of cellulose on which are chemically bound cationic chemical groups having a degree of substitution between 0.01 and 0.05. The rate of flow and the clarity effect are correlated to the degree of substitution of the utilized cationically modified cellulose, and the pigment adsorption, i.e. the adsorptive properties of the filter sheet, are correlated to the percent by weight of the cationically modified cellulose to the total amount of cellulose contained in the filter sheet. By utilization of these correlations, modified asbestos-free filter sheets can be produced which are adapted to given applications.