A memory system includes a plurality of memory devices, a controller configured to control the plurality of memory devices, and at least one channel connected between the plurality of memory devices and the controller. The at least one channel includes input/output data lines and control signal lines, which are connected with the plurality of memory devices, and chip enable signal lines respectively connected to each of the plurality of memory devices, wherein the chip enable signal lines enable the plurality of memory devices independently. The controller sends a read command or a program command to one of the plurality of memory devices, and while the one of the plurality of memory devices is performing an internal read operation in response to the read command, the controller reads data from another one of the plurality of memory devices, or while the one of the plurality of memory devices is performing an internal program operation in response to the program command, the controller programs data to another one of the plurality of memory devices.