This study is motivated by the depletion of fossil fuels in nature, which is inversely proportional to the higher level of fuel oil consumption, so the need for alternative fuels, namely biodiesel. It is also intended to find out the sample physicochemical properties, the effect of bioadditive addition of orange essential oil on the performance and exhaust emissions of diesel engines. The process in this study is to produce biodiesel with waste cooking oil using an esterification and transesterification process. Biodiesel samples containing the bioadditive orange essential oil on B20 biodiesel with varying volume fraction (0; 0.1; 0.15; 0.2). Engine performance testing uses a 2184 cc Mazda R2 engine with variations in engine speed (1700; 1900; 2100 and 2300 rpm). The results show that engine performance characteristics consist of torque, brake power, and thermal efficiency value increasing in 2.5. The value of exhaust gas emissions such as carbon monoxide and hydrocarbon decreases by 5, while the value of carbon dioxide increased in 4 using B20 biodiesel with orange essential oil bioadditive 0.2 at 2300 rpm. © 2021 Author(s).