A new class of malolactonate polymers and copolymers were synthesized, starting from the corresponding lactones, and then Characterized. Different lateral groups were selected for these polyesters to achieve a wide range of materials characteristics and possible biological recognition. The monomers were prepared according to two established procedures, which gave rather good overall yields. The polymers were obtained by the anionic ring-opening polymerization of the corresponding four-member ring monomers in the presence of a quaternary ammonium salt: as the initiator. Final macromolecular and thermal characteristics were in agreement with the designed monomer structures. Molecular weights in the range 4-20 kDa were obtained, as a result of chain transfer reactions. The prepared polyesters displayed stability up to 200 degreesC, and, when tested in preliminary cell culture experiments, provided indications for future applications in the biomedical field.