Abstract: An integrally bladed rotor is constructed from a plurality of layers of organic matrix composite material wound together in a spiral fashion to form the disc portion of the rotor, and at each rotor blade position at least the outermost one of the layers is turned substantially radially outwards from the periphery of the rotor disc to form a blade. Each blade is finished with further pieces of organic matrix composite material bonded into position on the. An encircling blade tip shroud may be formed by further layers of material wound around the tips of the blades in conjunction with closed loop inserts in the spaces between blades.