Abstract- Bio-diesel is proved as an attractive alternative fuel for use in diesel engine due to its renewable nature for a short span of time. Bio-diesel has several advantages among other new renewable and cleans alternative fuel in terms of availability, performance and emission. The objective of this paper is to prove waste vegetable bio-diesel oil as an alternative fuel for diesel engines. Methanol with NaOH catalyst give the best result in terms of bio-diesel yield (98 weight %). Among the metal chloride catalyst, Fe and Al obtained the highest bio-diesel yield (97 & 86 weight %). The molar ratios 6:1 give the optimum bio-diesel yield (97 weight%). The temperature was the most dominant factor which affects the reaction time and biodiesel yield. Waste vegetable oil, bio-diesel gave the performance and emission characteristics nearer to that of petroleum based diesel, making it a promising renewable sourse for the diesel engines. Keywords - Waste vegetable oil; Waste frying oil; Waste cooking oil; Bio-diesel yield. 1. Abbreviation: WVO : Waste Vegetable Oil WFO : Waste Frying Oil WCO : Waste Cooking Oil FFA : Fee Fatty Acid PBD : Petroleum Based Diesel ntroduction Energy is vital for social and economic growth for the entire mankind and, our economy significantly depends on the continuing accessibility of energy from sources that are economical, Iaccessible and environmentally friendly. The world's energy demand has enormously (629 quadrillion Btu, International Energy Outlook 2016) increased which leads the shortage and depletion of conventional sources [1-2]. The world's petroleum reserves are limited and extensive use of petroleum products has increased our concern towards alternative energy resources. Fossil fuels are the main cause of increased global carbon dioxide, carbon monoxide and other pollutant level, a consequence of global warming and health problem. Therefore, it is the cause of concern and have encouraged research world-wide for alternative sources of energy. Biofuels are emerging as substitutes for fossil fuel and among the biofuels, bio-diesel derived from Bio-Diesel Derived from Waste Vegetable Oil as an Alternative Fuel for Diesel Engine: A Review Shiv Kumar Ray 1 Mechanical Engineering Department, Research Scholar, NIT Patna Om Prakash Mechanical Engineering Department, Professor, NIT Patna Corresponding Author; Tel: +91 778281400 International Conference on Recent Advances in Mechanical Engineering (RAME- 2016) shivroy2k5@gmail.com, om.prakash@nitp.ac.in Shiv Kumar Ray, Om Prakash 563