According to an exemplary embodiment of the inventive concept, there is provided a nonvolatile memory device comprising: a memory cell region including a first metal pad, a peripheral circuit region including a second metal pad and vertically connected to the memory cell region by the first metal pad and the second metal pad, a memory cell array, in the memory cell region, comprising a plurality of memory cells, a plurality of word lines and a bit line connected to the memory cells, wherein each memory cell is connected to one of the word lines, a voltage generator, in the peripheral circuit region, supplying a plurality of supply voltages to the memory cell array, a control logic circuit, in the peripheral circuit region, programming a selected one of the memory cells connected to a selected one of the word lines into a first program state by controlling the voltage generator, and a verify circuit, in the peripheral circuit region, controlling a verify operation on the memory cell array by controlling the voltage generator, wherein the verify circuit controls a word line voltage applied to at least one unselected word line not to be programmed among the plurality of word lines in the verify operation and a bit line voltage applied to the bit line connected differently from a voltage level of a voltage applied in a read operation of the nonvolatile memory device.