The production of biodiesel has received considerable attention throughout the world in the past few years. As an alternative to petrodiesel, biodiesel is a renewable fuel that is derived from vegetable oils and animal fats. However, the existing biodiesel production process is neither completely "green" nor renewable because it utilizes fossil fuels, mainly natural gas as an input for methanol production. Also the catalysts currently in use are highly caustic and toxic. The purpose of this article is to propose a new concept that uses waste vegetable oil and non-edible plant oils as biodiesel feedstock and non-toxic, inexpensive, and natural catalysts that overcome the limitation of the existing process. The economic benefit of the proposed method is also discussed. The new concept will render the biodiesel production process truly green.