A semiconductor memory device and a memory system including the same are provided. The semiconductor memory device includes a memory cell array including memory blocks, a local parity memory block, and a register block. The memory blocks respectively store pieces of partial local data in response to a plurality of column selection signals, or a first partial global parity in response to a global parity column selection signal. The local parity memory block stores local parities of local data in response to the plurality of column selection signals, or a second partial global parity in response to the global parity column selection signal. The register block generates a global parity including the first partial global parities and the second partial global parity. Each piece of local data includes the partial local data, and the global parity is a parity of the pieces of local data and the local parities.