A method of operating a nonvolatile memory device includes precharging bit lines coupled to strings, supplying a first verification voltage to a selected word line and supplying a pass voltage to word lines other than the selected word line, supplying a first sense pulse to switching elements coupled between the bit lines and sense nodes and detecting memory cells, each having a threshold voltage higher than the first verification voltage, supplying a second verification voltage higher than the first verification voltage to the selected word line and supplying the pass voltage to the word lines other than the selected word line, and supplying a second sense pulse to the switching elements and detecting memory cells, each having a threshold voltage higher than the second verification voltage.