In a method of programming data in a nonvolatile memory device including memory cells and a page buffer, the memory cells are electrically connected to wordlines and bitlines, and the page buffer controls the memory cells. In a first program time period of a first program loop, a program voltage having a first program voltage is applied to a selected wordline that is electrically connected to a target memory cell, and a bitline shut-off signal having a first delay is applied to the page buffer. The program voltage is applied to the selected wordline multiple times during one program loop while a magnitude of the program voltage is changed. The delay of the bitline shut-off signal corresponds to a time period during which the bitline shut-off signal maintains a ground voltage.