Air pollution caused by diesel emissions, especially NOx, particulate matter, carbon monoxide and unburned hydrocarbons, has been a noteworthy matter. In Europe and the United States, legislative efforts towards improving air quality not only lead manufacturers to develop and introduce further improved emission control systems, but also the trigger demanding requirements on the oil industry towards producing advanced fuels. Therefore, much work on the effects of fuel properties on the emissions and engine performance has been performed worldwide. The fuels produced by the refineries usually comply with the existing specifications. However, alterations in the fuel properties may occur through the supply chain to the service stations due to failures of the distribution system or adulteration with lower value and taxation fuels (heating oil, marine diesel or industrial solvents). In this paper, exhaust emission and fuel consumption measurements from a single-cylinder, stationary diesel engine are presented. The engine was fuelled with automotive fuel, which was adulterated with white spirit in proportions up to 20 percent. Prior to the exhaust emission measurements, the base fuel and their blends with white spirit were studied in terms of their physicochemical properties. The emission tests included unburned hydrocarbons (HC), nitrogen oxide (NO), nitrogen oxides (NOx), carbon monoxide (CO) and particulate matter (PM) emission measurements under various loads up to 5 hp. The experimental results showed that the four types of the adulterated diesel fuel investigated increased NO, NOx, CO, HC emissions compared to the automotive diesel fuel but decreased the PM emissions. Additionally there is a decrease of fuel consumption in lower loads and a slight increase in the heavy loads.