A new type of catalyst for exhaust emission control of Diesel engines has been developed by a catalyst producer in cooperation with engine/heavy duty truck manufacturers. This so-called Sorption/Oxidation (“SO”)-catalyst is an extruded TiO2-type and works as a HC-trap as well as oxidation catalyst for hydrocarbons. In addition, a certain amount of particle matter was reduced, depending on type of engine, fuel sulfur content and test cycle. Due to its unique composition, i.e. oxides of titanium (80 wt %), tungsten and vanadium, the catalytic selectivity results in very low formation of sulfates as well as excellent resistance against sulfur compounds. The geometry of the catalyst prototypes corresponds to standard monoliths of 5,66″(144mm) in diameter and suitable lengths to be installed in standard mufflers. Since 1996, several buses and trucks have been equipped with SO-catalysts and are still in operation without problems.