In a semiconductor memory device and an internal data transmission method thereof, the device includes a memory controller, a pair of data lines, and a plurality of memory banks. During an internal data transmission operation, the memory controller externally receives and stores a source address and a target address in response to an externally applied command and outputs an internal control signal and an internal address signal using the source address and the target address. The internal control signal includes an internal write signal and an internal read signal. Transmission data is transmitted on the pair of data lines during the internal data transmission operation. The plurality of memory banks read the transmission data stored in a region corresponding to the source address in response to the internal read signal, transmit the transmission data on the pair of data lines, and write the transmission data transmitted on the pair of data lines in response to the internal write signal. During the internal data transmission operation, the transmission data is transmitted from the region corresponding to the source address to a region corresponding to the target address, and is not output external to the semiconductor memory device.