For the production of linear monocarboxylic acid esters with 6 to 26 carbon atoms vegetable oils or animal oils, which may or may not be neutral, are reacted with monoalcohols having a low molecular weight, for example 1 to 5 carbon atoms, in the presence of a catalyst that is selected from among zinc oxide, mixtures of zinc oxide and aluminum oxide, and the zinc aluminates that correspond to the formula:ZnAl.sub.2 O.sub.4, x ZnO, y Al.sub.2 O.sub.3(with x and y each being in the range of 0-2) and having more particularly a spinel type structure, thereby enabling the direct production in one or more stages, of an ester that can be used as a fuel or combustible and a pure glycerine.