Mathematical expressions are presented in this paper that correlate the exhaust emissions from a single-cylinder diesel engine with some of the most important properties of the fuels used. Exhaust emissions measured were carbon monoxide, unburned hydrocarbons, nitrogen oxides, and particulate matter. The experiments were performed using a matrix of 68 fuels, The cetane number of the fuels covered the range 42-58, the density varied between 0.84 and 0.860 g/mL, and the sulfur content varied from 0.05 to 0.20 wt 40, All predictions were based on specific points of the distillation curve, the cetane number, and the density of the fuels. In the case of particulate matter emissions, sulfur content was also employed. Very good predictions were obtained for all the emissions considered. The aromatic content was not used as a predictor variable because it was found to have a strong intercorrelation with the cetane number, density, and the 90% distillation point.