Four different types of vegetable oils of Turkish origin (sunflower, corn, soybean, and olive oil) were blended with grade 2-D diesel fuel at a ratio of 20/80 (v/v). Blends were investigated in a diesel engine with a precombustion chamber at speeds between 1200 and 2100 rpm. Vegetable oils, diesel fuel, and fuel blends were characterized according to standard test methods. It was found that for short-term use, the fuel blends have engine characteristics similar to the baseline diesel fuel. Fuel blends also display less smoke emissions than diesel fuel.