Abstract: The growing concerns for environmental sustainability, economic and energy security had made it obligatory to source energy alternatives that harmonize environmental friendliness with biodegradability, renewability, and less reliance on petroleum products dependence. One of such energy sources is called biodiesel. Wide range of substrate; vegetable oils e.g. palm oil, soybean oil, sunflower oil, coconut oil, rapeseed oil, micro algal oils, animal fats, waste products of vegetable oil refinery, used frying/cooking oils was used in its production. To produce biodiesel with these substrates conventionally is complex, as the method is faced with limitations in the downstream processing costs, byproducts recovery and environmental issues. Enzymatic method, involving enzymes particularly lipases in a process of alcoholysis with waste cooking oil emerged to be efficient in curtailing the problems. The potentiality of the waste cooking oil for this purpose among other applications qualified it as a resourceful waste in view of the fact that no concrete waste definitions limit it to only waste. This review focuses distinctively on how biodiesel fuel is produced by lipase catalysis of waste cooking oil, waste concept and definitions and how waste oil can be a viable recourse. Sources of different lipases and substrates were reviewed to include specific substrate modifications to describe the current substrate used in this article. Thus, the economic feasibility of biodiesel production from waste cooking oil is conclusively viable.