Endoscopic endonasal dacryocystorhinostomy (EE-DCR) is an effective treatment for dacryocystitis. Aneurysmal rupture is generally not considered a complication of EE-DCR under general anesthesia. Here, we present a patient with intracerebral and subarachnoid hemorrhage secondary to the rupture of an undiagnosed intracranial aneurysm during EE-DCR. Clinicians should be aware of such fatal complications when using any vasoconstrictor intraoperatively.