The esterification of various hydrophilic diols with fatty acids catalyzed by Lipolase(TM) was carried out in water-in-oil (w/o) microemulsion systems stabilized with sodium(bis-2-ethylhexyl)sulphosuccinate (AOT) as surfactant in isooctane. Mono- and di-esters were selectively synthesized with high reaction rates. The product distribution depends on substrates concentration. Microemulsions appear to be an effective and fast system for esterification of diols.