A method of driving a non-volatile memory device includes programming a plurality of memory cells based on a first data copied from a program data buffer to a verification data buffer, verifying the memory cells by overwriting a result of the verification of the programmed memory cells to a verification data buffer, and re-verifying the memory cells by repeating the programming and verifying operations at least once with respect to the memory cells that were successfully verified, based on the verification result written to the verification data buffer. A non-volatile memory device includes a program data buffer storing first data, a verification data buffer copying and storing the first data, a plurality of memory cells programmed based on the data stored in the verification data buffer, a comparator comparing data stored in the verification data buffer with data read out from the programmed memory cells and outputting comparison data generated based on a result of the comparison to the verification data buffer, and a control unit controlling the program data buffer, the verification data buffer, the memory cells, and the comparator to additionally program or verify the memory cells that were successfully verified, based on the first data.