An apparatus for retaining a bearing assembly on the neck of a roll in a rolling mill. The apparatus includes an adaptor element having outwardly projecting first lugs circumferentially separated by first flutes. Fasteners detachably secure the adaptor element to a distal end of the roll neck. A locking element, which comprises an integral component of the bearing assembly, has inwardly projecting second lugs circumferentially separated by second flutes. The locking element is rotatable between an unlocked position at which its second lugs are aligned with the first flutes of the adaptor element to accommodate axial shifting of the bearing assembly onto and off of the roll neck, and a locked position at which its second lugs are aligned with the first lugs of the adaptor element to axially retain the bearing assembly on the roll neck.