The invention relates to a method for preparing fatty acid esters particularly used as bio-diesel fuel from whole oleaginous grains, characterized in that it comprises the following successive steps: preheating the whole non-husked grains; flattening the oleaginous grains; drying the flattened grains in order to obtain a water content and a volatile material content between 0.5 and 2.5%, and preferably between 1.5% and 2%; performing a transesterification by contacting the dried, flattened grains with an alcoholic medium in the presence of a catalyst; separating the liquid and solid phases resulting from the transesterification; neutralising the liquid phase from step d); and removing the alcohol and separating the glycerine from the fatty acid esters.