An example operating method of a nonvolatile memory device includes applying a first verification voltage to selected memory cells in a first program loop that verifies pass or fail of a first program state among a plurality of program states, applying a second verification voltage to the selected memory cells in the first program loop that verifies pass or fail of a second program state among the plurality of program states, applying a program voltage to the selected memory cells in a second program loop, and verifying, based on the program voltage being applied to the selected memory cells, pass or fail of the first program state and the second program state for the selected memory cells based on a result of applying the first verification voltage and a result of applying the second verification voltage.