Emission characteristics and performance of Neem seed and Camelina Sativa based biodiesel in diesel engine was studied. The engine test was carried out using diesel fuels (B0), 5% and 10% (volume) blends of Neem and Camelina Sativa oil methyl esters of NB5, NB10, CB5 and CB10. The Engine performance of these fuels was tested in a 1.9 Multijet diesel Engine. The blends met the EN 14214 and ASTM D6751 standards. Performance test of the Engine shows that CB10 biodiesel fuels produced better BP and averagely high BSFC compare to the diesel fuels all through the ranges of Engine speeds examined. The Emission test results also shows that NB5, CB5, NB10 and CB10 fuels reduced the average emissions of CO by 4.84%, 8.79%, 10.77% and 12.09%, for HC and CO2 their emission were 6.48%, 12.96%, 16.67%, 20.37%; and 2.64%, 4.55%, 5.72%, 6.74% compared to diesel fuels. NOx emission of the blends has higher emission values of 18.7%, 3.14%, 19.33%, and 19.78%, for NB5, CB5, NB10, and CB10 fuels compared to conventional fuels. CB10 produces lower emissions than other biodiesel fuels, thus reducing major pollution and ensuring environmental safety. CB10 can be used as a replacement for diesel fuels in unmodified engines. •Biodiesel is generally referred to methyl esters (ME) of vegetable oil.•Biodiesel reduces CO emission.•Biodiesel is predominantly comprises of triglycerides and free fatty acids.•Universally, there are over 360 oil-producing crops.