Biodiesel from pure and used canola oil is produced by transesterification process in this study. Quality of biodiesel is examined according to ASTM 6751: biodiesel standards and testing methods. Important fuel properties of biodiesel, such as heating value, cetane index, viscosity, and others are also investigated. A direct injection (DI) diesel engine is tested with biodiesel-diesel and canola oil-diesel blends for performance and emissions at high idling operations. Three fuel series are examined: pure canola biodiesel, used canola biodiesel and pure canola oil series. In all the series, fuels are blended with petroleum diesel 2-20 vol.%. Engine performance is examined by measuring brake specific fuel consumption and fuel conversion efficiency. The emission of carbon monoxide (CO), hydrocarbon (HC), nitric oxide (NO), nitrogen dioxide (NO2), nitrogen oxides (NOx), carbon dioxide (CO2) and others are measured. Pure and used canola biodiesel blends show very similar fuel properties, engine performance and emissions. CO and HC emissions from biodiesel-diesel blends are significantly less than neat diesel fuel. Even pure canola oil up to 5% in diesel fuel can show significantly less CO emissions than that of diesel fuel. Up to 5% biodiesel and canola oil in diesel fuel, NOx emissions either can reduce or maintain similar level to that of diesel fuel. (C) 2013 Elsevier Ltd. All rights reserved.