The book begins with an introduction to the range of issues associated with fossil fuel reserves as well as issues related to the environment. Among the issues, is the supply of petroleum resources are dwindling, global warming and the rise in petroleum prices volatile. In addition, it also led to the introduction to the types of waste oil as well as its characteristics. Next, it describes techniques for conventional biodiesel conversion processing that is chemically and biologically as well as the latest methods of biodiesel conversion processing performed by the microwave assisted. The physical and chemical properties of the waste oil was obtained and compared with the characteristics of the diesel fuel. The base oils discussed here is crude palm oll, refined, bleached and deodorized (rbd) palm oil and waste cooking oil (wco). Features of biodiesel fuel, such as viscosity, calorific value, density, and many others have been compared with biodiesel standards. To enable the usage of sustainable biodiesel in diesel engines, gas turbines and industrial spray combustion, suggested that the use of biodiesel conversion process performed by the microwave. The advantage of this technique is described in the conclusion of this book.