The effect of sulfur on diesel emission control is reviewed in this paper. Diesel exhaust differs from that of petrol engine exhaust in two major characteristics. Firstly, diesel exhaust contains a far higher amount of particulate matter, and secondly, the exhaust is far leaner, that is, far more oxidizing than a typical exhaust from petrol engines. Under these conditions, the conventional three-way catalysts are not effective in reducing NOx. Emission from diesel engines is a complex phenomenon. The composition, the properties and the amount of these emissions depend on strictly technical parameters such as engine design and engine operation characteristics and on fuel and lube oil composition. Diesel fuel contains a small amount of sulfur which has an adverse effect even on the raw particulate emissions. The investigations on the effect of sulfur on hydrocarbons, CO and NOx abatement in diesel exhaust gas is reviewed together with the newest technologies to avoid catalyst deactivation by unwanted SO2 reactions.