Abstract: The present invention describes a head for machine tool on which an electro-spindle is mounted and in particular it describes a tilting head for machine tool on which an electro-spindle is mounted. In one embodiment the invention comprises a tilting head for machine tool comprising: one support element coupled to said tilting head; one electro-spindle; one cradle suitably shaped to incorporate and hold said electro-spindle pivoted on said support element so that it can turn around an axis perpendicular to the axis of said tilting head; said electro-spindle being set up to have mechanic, electric, pneumatic and hydraulic connections with said cradle; wherein said connections of said electro-spindle are of the releasable type so that said electro-spindle is interchangeable and can be rapidly coupled to and uncoupled from said cradle.