The invention relates to a rotor (12) for an axial flow turbomachine, comprising a plurality of rotor discs (10, 14, 16, 24, 26) that are arranged in stacks and clamped together with at least one tie rod (58). In order to provide a particularly inexpensive rotor (12) with compact design, particularly suitable for especially high pressure conditions with comparably high compressor mass flow, it issuggested that at least one of the rotor discs (24), (26) of the rotor (12) comprises a smaller outer diameter than one of the neighboring rotor discs (16) and that the difference in diameter is compensated by a drum (28) surrounding the rotor disc (24, 26) with the smaller outer diameter as a ring. The drum (28) can be made of a heat resistant material. The rotor discs (24, 26) surrounded by thedrum can be made of a less expensive material, thus saving costs. Furthermore, the drum (28) can comprise at least one more blade ring than the rotor discs (24, 26) that are surrounded by the drum.