Nonvolatile memory devices and methods of fabricating the same are provided. A semiconductor substrate is provided having a cell field region and a high-voltage field region. Device isolation films are provided on the substrate. The device isolation films define active regions of the substrate. A cell gate-insulation film and a cell gate-conductive film are provided on the cell field region of the substrate including the device isolation films. A high-voltage gate-insulation film and a high-voltage gate-conductive film are provided on the high-voltage field region of the substrate including the device isolation films. The device isolation film on the high-voltage field region of the substrate is at least partially recessed to provide a groove therein.