A scrubbing controller of a semiconductor memory device includes a scrubbing address generator and a weak codeword address generator. The scrubbing address generator generates a scrubbing address for all codewords in a first bank array of a plurality of bank arrays in a first scrubbing mode. The scrubbing address is associated with a normal scrubbing operation and changes in response to an internal scrubbing signal and a scrubbing command. The weak codeword address generator generates a weak codeword address for weak codewords in the first bank array in a second scrubbing mode. The weak codeword address is associated with a weak scrubbing operation and is generated in response to the internal scrubbing signal.