A memory module having an address mirroring function is provided. The memory module includes a register that allows mode registers of first memory chips of a first rank and mode registers of second memory chips of a second rank to be identically programmed in response to a mode register set (MRS) command during a rank-merged test mode. The register sets address signals, which are symmetrically connected to the first and second memory chips through through-via-holes (TVHs) or blind-via-holes (BVHs) of a printed circuit board, to be selectively mirrored.