The present invention relates to lightweight sprocket, consisting of a central portion (1) made from light metal alloy, to which a peripheral toothed portion (2) made from ferrous alloy is joined, using rivets (3) for joining said portions (1,2), where said joining is created between radial beams (21) of the peripheral toothed portion (2) and pocket-like recess (13) in the central portion (1), radial beams (21) being overlapped across bottoms of pocket-like recesses (13), and where a thickness of radial beams(21), at least over the joining area, is decreased by 10 to 60%, in relation to full thickness of said toothed peripheral portion (2), and a thickness of a bottom of the pocket-like recess (13) in the central portion (1) is decreased by 20 to 70%, in relation to full thickness of the central portion (1) of the sprocket.