The petrous apex is a complex region of temporal bonedue to its close proximity to vital structures. Cholesteatomain the petrous apex is rarely encountered, and mostcases are congenital. These lesions often invade the labyrinthand facial canal before they are diagnosed. However,clinical findings are nonspecific and diagnosis maybe delayed. Moreover, surgery of petrous apex cholesteatomais extremely difficult. Several approaches havebeen reported for removal. In this article, a case of congenitalpetrous apex cholesteatoma with delayed diagnosiswho treated with modified transcochlear approachwas presented.