A semiconductor memory device which includes a memory cell array, an error injection register set, a data input buffer, a write data generator, and control logic. The error injection register set stores an error bit set, including at least one error bit, based on a first command. The error bit set is associated with a data set to be written in the memory cell array. The data input buffer stores the data set to be written in the memory cell array based on a second command. The write data generator generates a write data set to be written in the memory cell array based on the data set and the error bit set. The control logic controls the error injection register set and the data input buffer.