We surgically clipped an IC-PC aneurysm in an 82-year-old woman after opening the oculomotor cistern. The internal carotid artery was sclerotic and tilted to the anterior clinoid process. The aneurysm was very small and embedded beneath the tentorial edge. To expose enough space for aneurysm neck clipping without a temporary carotid artery clamp, the oculomotor cistern was opened along the oculomotor nerve from the oculomotor porus to just lateral to the tip of the anterior clinoid process, and the roof of the cavernous sinus was resected medially to the oculomotor nerve. The aneurysm neck was clipped with neither cavernous sinus opening nor oculomotor nerve injury.