A series of copolymers were prepared by ring-opening polymerization of e-caprolactone and (R,S)-b-butyrolactone, using zinc lactate as catalyst. The resulting PCL/PBL copolymers were characterized by various analytical techniques such as NMR, SEC, DSC and X-ray diffraction. The CL/BL ratio was higher in the copolymers than in the feeds, indicating a higher reactivity of e-caprolactone with respect to b-butyrolactone. The copolymers appeared semi-crystalline, the crystalline structure being of the PCL-type. Compression molded polymer films were allowed to degrade in a pH = 7.0 phosphate buffer containing pseudomonas lipase. Data showed that the copolymers degraded faster than the PCL homopolymer. Various soluble degradation products were detected in the degradation medium. ESEM micrographs confirmed the enzymatic degradation occurred by surface erosion.