In the present study investigates the effect of bio-ethanol on the performance and emissions of a biodiesel blend fueled compression ignition engine. The experiments are conducted using pongamia biodiesel blend B20 (20% pongamia biodiesel +80% diesel) with 5, 7.5 and 10% (v/v) of bio-ethanol on a four stroke single cylinder diesel engine. The tests are conducted at different load conditions. Performance and emissions characteristics are investigated for different bio-ethanol compositions. The results show that the brake thermal efficiency is maximum for B20E7.5 blend with a minimum brake specific fuel consumption. Carbon monoxide emission is minimum for B20E7.5 blend and NOx emission decreases as the bio-ethanol percentage is increased from 5 to 7.5%. The study reveals that 7.5% bio-ethanol with B20 pongamia biodiesel blend results better performance and emission characteristics.