Provided are a nonvolatile memory device and a method of reading the same. The nonvolatile memory device includes: a memory cell; a transistor disposed between a common source line and the memory cell; and a control logic for controlling a bias voltage of the transistor to reduce the amount of current flowing into the common source line during a read operation. The method includes: applying a read voltage to the memory cell; and controlling a bias voltage of the transistor to reduce the amount of current flowing into the common source line.