A series of emissions tests were completed with 2 light duty diesel passenger cars, a Volkswagen and Oldsmobile, to examine the sensitivity of emission rates and composition to fuel. Four fuels including 3 petroleum distillates and an oil shale distillate were used in the program. The tests included 6 driving schedules. Determinations of gaseous emission rates, including total hydrocarbon, carbon monoxide, and oxides of nitrogen, and particulate emission rates were completed. Compositional characterization of the particulate matter included dichloromethane soluble organic fraction, benzo(a)pyrene, pyrene, nitropyrene, Ames TA-98 bioassay, and trace elements.Both gaseous and particulate mass emission rates were insensitive to the fuels examined in this program. The polynuclear aromatic hydrocarbon compounds associated with the particles varied between fuels, but were not well correlated with the fuel polynuclear aromatic hydrocarbon content. Ames TA-98 mutagenic activity was elevated with the oil shale distillate fuel in the Volkswagen but reasonably consistent for all other vehicle-fuel combinations examined.