A nonvolatile memory device includes a plurality of vertical NAND flash memory cells arranged in a three dimensional (3D) structure, a first memory block disposed in the 3D structure and having memory cells selected by a first ground selection line and a second ground selection line, wherein the first and second ground selection lines are electrically separated from each other, a second memory block disposed in the 3D structure and having memory cells selected by a third selection line and fourth selection line, wherein the third and fourth ground selection lines are electrically separated from each other, and a pass transistor that transfers a driving signal to turn on ground selection transistors respectively connected to the first and third ground selection lines in response to a block selection signal.