A flow-through ceramic monolithic catalyst; containing bulk CeO2 as the catalytically active component, is reported for the catalytic oxidation of the liquid portion of the particulates present in diesel engine exhausts. This new technology has been successfully implemented into medium duty trucks in the U.S. beginning in 1994 meeting all required emission standards. Catalyst screening and engine durability/aging results and a proposed mechanism of operation are presented. The addition of a proprietary zeolite as a hydrocarbon trap and a small amount of Pt to the platform CeO2 catalyst enables european emission standards for CO, HC and particulates to be met. Commercialization of this technology in Europe began in the first part of 1996.X?