A flash memory device and method of programming a flash memory device which include an array of memory cells arranged in rows and columns. A method includes programming memory cells of a selected row with loaded data; determining whether the memory cells of the selected row are successfully programmed; when the judgment result is determined as a unsuccessful program operation, determining a reprogram operation according to flag information indicating an on/off state of the reprogram operation stored in the flash memory device; and when the flag information indicates an on state of the reprogram information, reprogramming the loaded data to memory cells of a different row from the selected row.