New polyolefin supported sulphonic acid catalysts were used in the esterification of acetic acid with methanol. The new catalysts turned out to be stable and active in esterification, The esterification kinetics was modelled with a mechanistic rate equation, the parameters of which were determined by non-linear regression, The esterification rare constant of the most active modification of the new catalyst was 9.6 x 10(-10) dm(9)/(mol(2) g min) at 55 degrees C, which clearly exceeds the corresponding value obtained with a traditional polyvinylbenzene supported catalyst, 1.5 x 10(-10) dm(9)/(mol(2) g min).