Waste cooking oil is one of the energy sources for its unique composition which contains glycerol, It can be a good base for producing biodiesel. The objective of this study is to perform the energy and economic analyses of biodiesel production from Waste Cooking Oil (WCO) by the conventional transesterification method at the Tarbiat Modares University, Tehran, Iran. Data is acceded by performed biodiesel machine, with three replications during spring season (2012) in the same condition. The volume of biodiesel machine is 2000 L and the area of this lab is 100 m2. The total energy input and energy output were calculated as 30.05 and 44.91 MJ L−1, respectively. The energy output/input ratio was 1.49 in biodiesel production. The shares of renewable and non-renewable energy were 77.31% and 22.69%, respectively from total energy input. The benefit to cost ratio was found to be 2.081 according to the result of economical analysis of biodiesel production. The mean net return and productivity from biodiesel production were found to be 1.298 $ L−1 and 0.946 kg $−1, respectively. The results showed that by applying ultrasonic and microwave instead of transesterfication and great managing, more benefit can be resulted.