Enzyme-catalyzed preparation of polymers offers several potentially valuable advantages over the usual polymerization procedures. This paper summarizes our successful use of lipase-catalyzed polycondensations to prepare both a series of achiral [AA-BBJx polyesters from simple bis(2,2,2- trichloroethyl) alkanedioates and diols and of an optically active, epoxy-substituted polyester having a stereochemical purity estimated to be greater than 96%, from racemic bis(2,2,2-trichloroethyl) trans- 3,4-epoxyhexanedioate and 1,4-butanediol. The somewhat less successful polycondensation of a series of A-B monomers is also described. All of the reactions were carried out at ambient temperature in anhydrous, low to intermediate polarity, organic solvents such as ether, THF, and methylene choride, using porcine pancreatic lipase (PPL) as the catalyst. Possible explanations for the difference between the A-B and AA + BB cases, based on NMR analysis of the reactions' progress are considered.