We experienced 15 surgical cases of petrous apex-11 cholesteatomas and 4 cholesterin granulomas-between January 2013 and July 2021. Among the four cases of cholesterin granuloma, one underwent transmastoid surgery, while the others received intranasal endoscopic surgery to create drainage routes. Among the 11 cases of cholesteatoma, 5 received initial surgery, and 6 were reoperations. The extent of the lesion based on Sanna's classification was supralabyrinthine in seven patients, massive in two, and infralabyrinthine in two. In the supralabyrinthine type, the middle fossa approach or combined approach of the middle cranial fossa and translabyrinthine approach was necessary in cases with severe extensions or those receiving reoperation. The minimally invasive procedure through the superior semicircular canal approach was performed in cases with a small extension. In the massive type, the transcochlear and middle fossa combined approach was used, while in the infralabyrinthine type, the infracochlear or infralabyrinthine approach was performed, depending on the localization and degree of the extension. The hearing was preserved in all cases of cholesterin granuloma and three cases of cholesteatomas. Since the petrous apex is located in the deepest part of the temporal bone, it is crucial to have a thorough understanding of the anatomy and select a surgical approach that considers the lesion and hearing.