The development of low-temperature premixed compression ignition (PCI) combustion strategies and the performance of diesel oxidation catalysts (DOC) are presented in this work. At moderate loads, low-temperature PCI combustion is shown to significantly reduce engine-out oxides of nitrogen (NOX) and soot emissions compared to a conventional diesel combustion strategy. The PCI load-range is limited by soot emissions at high engine loads and excessive carbon monoxide (CO), hydrocarbon (HC) emissions and low exhaust gas temperatures low engine loads. DOC formulations are investigated on a gas bench reactor using surrogate exhaust gas mixtures containing CO, O2, H2O, C11H24, C2H4 and N2. Light-off tests show delayed catalyst light-off in the presence of PCI exhaust. CO and HC are converted to 100% and 98% respectively under fully lit conditions. Engine experiments agree well with reactor experiments. DOC formulations containing zeolites adsorb HC at low temperatures. HC speciation shows that HCs of carbon number five and higher are trapped on zeolite at low temperatures. CO conversion is 100% through the fully active catalyst; HC conversion is lower compared to the reactor experiments.