A memory system that includes a memory device and a memory controller. The memory device includes a plurality of memory cells, and a first storage unit configured to store information about a weak cell from among the plurality of memory cells. The memory controller is configured to transmit an operation command signal to the memory device, and control an operation of the memory device by using the information about the weak cell provided from the first storage unit. If the operation command signal is related to an operation to be performed using a first of the memory cells and the first memory cell is the weak cell, the memory device is configured to transmit the information about the weak cell to the memory controller.