A nonvolatile memory device includes first and second impurity diffusion regions formed in a semiconductor substrate, and a memory cell formed on a channel region of a semiconductor substrate between the first and second impurity diffusion regions. The memory cell includes a stacked gate structure formed on the channel region, and first and second select gates formed on the channel regions and opposite sidewalls of the stacked gate structure. Since the first and second select gates are spacer-shaped to be self-aligned on opposite sidewalls of the stacked gate structure, a size of a memory cell is reduced to enhance an integration density of a semiconductor device.