In the present work, bio-diesel produced from Thevatia peruviana seed oil which is commonly called as Yellow oleander is blended with diesel to investigate the performance and emission characteristics of a naturally aspirated diesel engine. The testing is carried out under 8-mode testing cycle used for off-road vehicles. The extracted bio-oil is subjected to gas chromatography-mass spectrometer to obtain its fatty acid profile. It is then converted into biodiesel by transesterification process. The properties of bio diesel produced are conforming to EN14214 standards except for a slightly lower density. Two blends of B10, B15 with diesel are used for experiments. The reduction in power and torque is observed to be proportional to increasing blend ratio. Results show that there is a reduction of 15.71% of CO and 32.30% reduction in HC for B15 blend compared to base line diesel. However, CO2 and NOX emissions are found to be increased for blends as compared to baseline engine.