NOVELTY - Preparation of biodiesel (I) from Balanites aegyptiaca oil (II), comprises reacting (II) with 1-4C alkanol at a molar ratio of 1:12-1:3, at 25-100degreesC, under intensive mixture conditions, in the presence of a transesterification catalyst, and allowing the transesterification to occur while removing the glycerol formed during the reaction; washing the mixture of 1-4C alkyl esters of fatty acids with water to remove the catalyst; and recovering (I) comprising a mixture of the fatty acids and optionally Balanites aegyptiaca saponins.    USE - The invention deals about the preparation of biodiesel from Balanites aegyptiaca oil or nuts.    ADVANTAGE - The oil or nuts of the desert Balanites aegyptiaca is an excellent feedstock for the production of biodiesel. (I) can be used either alone or in blends with conventional diesel or other types of biodiesel. The Balanites aegyptiaca saponins acts as surfactant, which reduces the rate of corrosion and improve the performance of the engine.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for:    (1) the preparation of Balanites aegyptiaca oil from Balanites aegyptiaca whole seeds, comprising washing the Balanites aegyptiaca whole seeds with water to dissolve and remove the glycosides from the seed coat; drying the washed whole seeds; crushing the whole seeds to obtain a powder; extracting the powder to obtain a crude Balanites aegyptiaca oil; and filtering the crude Balanites aegyptiaca oil;    (2) a process for producing biodiesel from Balanites aegyptiaca crushed nuts, comprising homogenizing Balanites aegyptiaca crushed nuts with a 1-4C alkanol, at 25-100degreesC; reacting the homogenate with a transesterification catalyst; filtering the reaction mixture product; extracting Balanites aegyptiaca biodiesel comprising a mixture of 1-4C alkyl esters of fatty acids and optionally Balanites aegyptiaca saponins from the filtrate; neutralizing the mixture product and removing 1-4C alkanol; drying and filtering the product; recovering (I); and drying the filter-cake and extracting the dried filter- cake to recover additional Balanites aegyptiaca biodiesel left in the dried filter-cake; and    (3) a biodiesel fuel mixture obtained by transesterification of Balanites aegyptiaca oil or crushed nuts.