Novel, star-shaped, amphiphilic block copolymers composed of fully degradable poly(caprolactone) were synthesized by sequential addition polymerization. In the first step, four-arm macroinitiators were produced by ring-opening polymerization of caprolactone by initiation with pentaerythritol. Then block copolymers were synthesized by sequential addition of 4-(2-benzyloxyethyl)-epsilon-caprolactone to the four-arm macroinitiators. Star-shaped, amphiphilic block copolymers containing poly(caprolactone)-block poly[4-(2-hydroxyethyl)caprolactone] segments were obtained by catalytic debenzylation.