ABSTRACTEnergy is an important criterion in determining the world’s economy. Due to continuous industrial development, increase in population and standard of living leads to energy crisis and also increase in consumption of fossil fuels. The world is presently confronted with the dual crisis of fossil fuel depletion and environmental degradation. All countries are looking for a new energy source that will last for long period, and no environmental pollution. Biodiesel proves to be a good alternative to fossil fuels. But the viability of biofuel is also the key parameter for suggesting it as an alternate source for CI engines. The selection of optimum biodiesel with the appropriate blend for the IC engine plays a vital role in the energy sector. The objective of this study is to identify the apt fuel blend using hybrid Multi-Criteria Decision Making (MCDM) with various evaluating criteria and the alternatives.FAHP with TOPSIS and PROMETHEE are hybrid MCDM methods that are used to evaluate the suitable blend. FAHP is applied to find the relative weights of the criteria, while PROMETHEE and TOPSIS are used to identify the best alternatives. The performances of the MCDM methods were also analyzed with each other. A four-stroke single cylinder, constant speed, direct injection with a rated output of 4.4 kW was used for exploratory analysis. NOx, Smoke, HC, CO, CO2, BTE, EGT, ID, CD and MRP were considered as the assessment criteria. The priority ranking positions of the fuel blend alternatives are attained by FAHP with TOPSIS & PROMETHEE are B100<B80<B60<B40<Diesel<B20. From the results, it is observed that B20 is the best blend. The proposed models have significantly increased the efficiency of decision-making process for the engine researchers to identify the optimum fuel blend by minimising the noxious emissions.