Abstract The kinetics of alkaline hydrolysis of some typical esters, with unsaturation in the alkyl and the acyl portions, was studied. It was found that, in general, unsaturation results in enhancing the rate as compared to that of the corresponding saturated esters, provided that there is no conjugation between the double bond and the carboxyl carbonyl group. Oxalic esters hydrolyze relatively very fast due to the close proximity of the two ester groups. Rate constants for the alkaline hydrolysis of di-n-propyl-, di-isopropyl-, di-n-butyl-, di-s-butyl-, dicyclohexyl- and di-β-chloroethyl oxalates were obtained by using the theory of mass transfer accompanied by fast pseudo first-order reaction (diffusion method).