A nonvolatile memory device includes a cell array including a plurality of cell strings extending on a substrate in a vertical direction, a page buffer connected to a plurality of bit lines and configured to store sensing data of the cell array in a sensing operation, a voltage generator configured to provide voltages to a plurality of word lines and the plurality of bit lines, and an input/output buffer configured to temporarily store the sensing data received in a data dump from the page buffer and to output the temporarily stored data to an external device. The nonvolatile memory device further includes control logic configured to set a status of the nonvolatile memory device to a ready state after the sensing data is dumped to the input/output buffer and before recovery of the cell array from a bias voltage of the sensing operation is complete.