Well-defined block poly(epsilon-caprolactone)-b-poly(dimethiylsiloxane) (PCL-b-PDMS) copolymers with one or two PCL blocks were obtained via coordinated anionic polymerization of epsilon-caprolactone by using hydroxy terminated PDMS oligomers both as initiators and comonomers. Molecular weights of these copolymers were varied over a wide range between 7200 and 30400 g/mol and the formation. of copolymers with desired backbone composition were monitored by H-1 NMR spectroscopy and SEC. DSC studies illustrated the formation of two phase morphologies, with PDMS and PCL transitions respectively and the influence of the copolymers structure on. their thermal properties has been examined.