This study focuses on the conversion of chicken fat into chicken fat methyl ester (CFME) and its use in the diesel engine. Baseline fuel i.e., diesel and chicken fat biodiesel are the fuels tested to study their effect on the performance and emission characteristics of diesel engines. To enhance the performance and emission characteristics, ethanol up to 20% is added as an additive to the chicken fat biodiesel. The physiochemical properties revealed that the fuel blends properties are closer to the diesel fuel. The experimental investigations revealed that additive blended biodiesel enhanced the performance by reducing the brake-specific fuel consumption and increasing the brake thermal efficiency. Moreover, the emissions are considerably reduced by the additive blended chicken fat biodiesel. Therefore, chicken fat biodiesel can be considered as a substitute fuel to be used in the diesel engine without any modifications.