Recent changes in regulatory practices have brought about a need for speciated analysis of the volatile organic components of vehicle exhaust. The purpose of the study was to allow interested laboratories to participate in a Round Robin so that each could assess their speciation methodologies. 'Synthetic exhaust' samples were prepared of mixed DN-carbonyl standards deposited on DNPH-coated cartridges, and solutions of alcohol in water. The fifteen participating laboratories included automotive, contract, petroleum, and regulatory organizations. The results described in this paper consider only variability asociated with the analytical measurement of the samples that have already been collected in impingers or on cartridges. In general, alochols (methanol and ethanol) were quantified without difficulty. With the exception of acrolein and crotonaldehyde, the quantitation of the carbonyl samples was fairly good considering the variety of analytical methods that were employed.