A memory system and a method for recording/reproducing data thereof, the memory system including a flash memory, and a memory controller configured control an operation to record data on the flash memory or to reproduce the recorded data from the flash memory, wherein the memory controller includes an encoder configured to generate an Error Correction Code (ECC) from data that is to be recorded in the flash memory and to convert the generated ECC by using a particular ECC, a memory interface configured to record the data and the converted ECC to the flash memory, and a decoder configured to restore the converted ECC, which is read from the flash memory, by using the particular ECC and to detect and correct an error of the data, which is read from the flash memory, by using the restored ECC, and the particular ECC is an ECC with respect to 0xff data.