In this work, diesel fuel was mixed with biodiesel, biodiesel-alcohol, and biodiesel-alcohol-vegetable oil blends using the basic alcohols of ethanol, methanol and butanol. The exhaust gas emissions of a small diesel generator running on different fuel blends were compared and the combined effects of alcohol-vegetable oil fuel blends were studied. Blend ratios used in this study were diesel-biodiesel (70-30%), diesel-biodiesel-alcohol (70-20-10%) and diesel-biodiesel-alcohol-vegetable oil (70-20-5-5%). As compared to diesel-biodiesel blends, diesel-biodiesel-alcohol and diesel-biodiesel-alcohol-vegetable oil blends increase CO and HC emissions while reducing NOx emission. It was also shown that adding vegetable oil to diesel-biodiesel-alcohol blends improved emissions All the tested fuel blends produced the highest difference in CO and HC emissions at no-load and the smallest difference at full-load. (C) 2014 Elsevier Ltd. All rights reserved.