A method and device for copying-back data in a multi-chip flash memory device having first and second memory chips. The method may include reading first source data from a first source region of one of the memory chips; programming the first source data into a target region included in one of the memory chips and reading second source data from second source region of the other memory chip different from the memory chip including the target region. Reading the second source data may be carried out while programming the first source data.