A nonvolatile memory device includes a memory cell region including first pads and a peripheral circuit region including second pads. The regions comprises switches that are electrically connected with the pads, respectively, a test signal generator that generates test signals and to transmit the test signals to the switches, internal circuits that receive first signals through the pads and the switches, to perform operations based on the first signals, and to output second signals through the switches and the pads based on a result of the operations, and a switch controller that controls the switches so that the pads communicate with the test signal generator during a test operation and that the pads communicate with the internal circuits after a completion of the test operation. The peripheral circuit region is vertically connected to the memory cell region by the first metal pads and the second metal pads directly.