Copper(I)-catalyzed cycloaddition of synthetic and bacterial copolyesters bearing pendant alkyne group with mono-(6-azido-6-desoxy)-beta-cyclodextrin was carried out to synthesize beta-CD-functionalized copolyester. The synthetic "clickable" copolyesters were obtained by the ring-opening copolymerization of the propargyl-modified lactones and epsilon-caprolactone. The bacterial copolyesters containing an alkyne group were biosynthesized from a mixture of 10-undecynoic acid and hexanoic acid by the Gram-negative bacteria Pseudomonas oleovorans. The modified products of the "click" reaction were characterized by FT-IR, H-1 NMR spectroscopy, and DSC. Furthermore, the host guest capability of covalently attached beta-cyclodextrin moieties was proved by dynamic light scattering measurements.