In this experimental study, the engine performance and exhaust emissions of a diesel direct injection engine using mixed palm olein-soybean vegetable oil ethyl ester (POSEE) and methyl ester (POSME) were studied. The results of experimental studies have shown that the torque and the brake power output of the engine using biodiesels has a little lower value and the specific fuel consumption is higher compared to the engine using conventional disesel.It was also observed a decrease both at CO and HC emissions that indicated an advantage about exhaust emissions. Although methyl ester’s CO2 emission has decreased compared to the diesel fuel, NO and NOX emissions were higher with the biodiesels