Abstract: A catalyst for removing nitrogen oxides, carbon monoxide, and residual hydrocarbons from exhaust gases is made with the use of technical metal phthalocyanines and a carrier onto or into which the metal phthalocyanines are applied, whereupon the system composed of the carrier and metal phthalocyanines is treated, at temperatures above 120.degree. C., with nitrogen oxides and/or mixtures of nitrogen oxide and carbon monoxide and/or with oxygen and/or mixtures of oxygen and carbon monoxide or with nitrating or oxidizing solutions. Instead of activating by nitrating or oxidizing gases or solutions, the activation also may be effected by intimate mixing of metal oxide and metal phthalocyanine on and in a carrier.