An optical disk and a method of recording data in the optical disk are provided. When data is overwritten on a recordable and/or reproducible optical disk, the method includes performing linking in front of a physical cluster from which overwriting starts. According to the method, when overwriting is performed on a portion of an optical disk in which data has been recorded, or when overwriting is performed on a portion including a defective area, linking is performed in front of the portion on which the overwriting is performed or behind the defective area, thereby realizing reliable data recording and reproducing.