A method for operating a memory device includes: receiving a first read command and a first address; reading a first read data and a first error correction code from memory cells selected based on the first address; detecting and correcting an error of the first read data using the first error correction code; storing the first address as an error detection address in an address latch circuit; storing an error-corrected bit of the first read data and a position of the error-corrected bit of the first read data in a data latch circuit; and transmitting an error-corrected first read data to an external device.