A laboratory burner has been operated with paraffinic mixtures, aromatic mixtures, n-paraffins, cetane standard fuel mixtures, and diesel No. 2 to measure fuel effects upon the production of diesel odor. Of the variables studied which included aromatic content, volatility, cetane number and specific gravity, only aromatic content was found to have a significant effect upon measured odor intensity. Normal paraffinic fuels were found to produce comparable exhaust odor intensities as a function of stoichiometry, irrespective of wide variations in their properties. At lean stoichiometries, branched paraffinic mixtures were found to produce low LCO and high LCA concentrations compared to n-paraffins.