A method of 4-bit MLC programming a nonvolatile memory device includes inputting an mth program operation command and sequentially executing first to fourth logical page program operations according to first to fourth logical page program start voltages, each stored in first to fourth logical page program start voltage storage units, wherein a program voltage, which is applied at a time point at which a memory cell programmed higher than a lowest verify voltage while a program operation of each logical page is performed occurs for a first time, is updated to each logical page program start voltage.