The gas turbine engine rotor assembly includes a rotor disc with a plurality of sealing tabs projecting radially out from a peripheral surface of the rotor disc in the rear end portion thereof. A said sealing tab is disposed at a tip portion of a fixing member of the disc, formed between pairs of blade root slots, adjacent a trailing edge of the rotor disc. The sealing tabs help to reduce the leakage of secondary air out the back of a blade pocket defined between adjacent blades mounted on the rotor disc.