The authors have examined the influence of biocomponents of different origin on exhaust gases emitted from a light duty vehicle with a compression ignition engine. The car was fuelled with diesel fuel containing 20% V/V fatty acid methyl esters and diesel fuel with 13% V/V hydrotreated vegetable oils and 7% V/V fatty acid methyl esters. Commercial diesel fuel containing 7% V/V esters was a reference. The tests were performed on the chassis dynamometer in static engine operating conditions. It was stated that the addition of mentioned biocomponents into diesel fuel slightly changed the concentration of regulated components in exhaust gases with/without after-treatment devices. The presence of bio-components has reduced nitrogen oxide concentration in the treated exhaust gases as compared to the commercial diesel. We observed no trends of changes in unburned hydrocarbon concentrations depending on the type of tested fuels and presence of the diesel particle filter. Unburned hydrocarbons consisted mainly of fractions containing up to five carbon atoms per molecule. Whatever the type of fuel examined, carbonyl compounds such as formaldehyde and acetaldehyde were found only in the untreated exhaust gases.