The present paper examines two biodiesels named as fish oil methyl ester (FOME) and chicken oil methyl ester (CFME) produced from low-cost waste fish and chicken oils using the transesterification method, and their fuel properties were compared to EN 14214 and ASTM D6751 biodiesel standards. Then, each methyl esters were blended with the commercial diesel fuel (D2) with a ratio of 20% on volume basis, respectively and two fuel samples named as FOB20 (20% Fish Oil Methyl Ester and 80% D2 fuel) and CFB20 (20% chicken oil methyl ester and 80% D2 fuel) were obtained. An experimental study for investigating the effects of the blended fuels on engine performance and its exhaust emissions was performed by using a single cylinder, four stroke, direct injection and air-cooled diesel engine at different speeds under full load. According to the test results, it was observed that the brake power, torque values and the carbon monoxide (CO), unburnt hydrocarbon (UHC) and carbon dioxide (CO2) concentrations of blended fuels decreased while the NOx concentration and brake specific fuel consumption (bsfc) values increased compared to diesel fuel. (C) 2015 Elsevier Ltd. All rights reserved.