A method of operating a nonvolatile memory device comprises applying a read current with a first level to a nonvolatile memory cell comprising a variable resistance material, determining read data based on the applied read current, checking a syndrome corresponding to the read data to determine whether the read data is pass or fail, changing the read current from the first level to a second level, which is different from the first level, according to the determination of whether the read data is pass or fail, and performing a read-retry operation comprising applying the read current of the second level to the nonvolatile memory cell.