To program in a nonvolatile memory device include a plurality of memory cells that are programmed into multiple states through at least two program steps, a primary program is performed from an erase level to a first target level with respect to the memory cells coupled to a selected word line A preprogram is performed from the erase level to a preprogram level in association with the primary program with respect to the memory cells coupled to the selected word line, where the preprogram level is larger than the erase level and smaller than the first target level A secondary program is performed from the preprogram level to a second target level with respect to the preprogrammed memory cells coupled to the selected word line.