According to example embodiments, a read method of a nonvolatile memory device includes Disclosed is a read method of a nonvolatile memory device which includes selecting one of a plurality of vertical strings in a nonvolatile memory device, judging a channel length between a common source line and a selected one of the plurality of vertical strings, selecting a sensing manner corresponding to the judged channel length, and performing a sensing operation according to the selected sensing manner. The plurality of vertical strings may extend in a direction perpendicular to a substrate of the nonvolatile memory device.