The isolation and structural characterization of a methylaluminium(bisphenoxide)-epsilon-caprolactone, complex is reported. While the three-coordinate methylaluminium complex was found not to catalyze the polymerization of epsilon-caprolactone, its oxygenation led to the formation of an aluminium methoxide compound, which appeared to be a very good initiator. The relative propensity of the Al-X bonds for monomer insertion in the initial step of polymerization is also discussed.