This guideline describes the state of the art of catalytic waste gas cleaning. It serves as a basis for the choice of methods, design and operation as well as the ecological and economic evaluation of plants and catalysts for waste gas cleaning. Questions related to the practical application of the methods have obtained top priority. The guideline covers the application of the catalytic waste gas cleaning in stationary plants and processes only. The catalytic waste gas cleaning of flue gases of power plants is described in guideline VDI 3927 Part 1.