A 62-year-old male presented with an unusually large mycotic aneurysm mimicking a saccular aneurysm manifesting as coma and hypotension. Computed tomography showed intracerebral and intraventricular hemorrhage. He was in septic shock due to acute infectious endocarditis. Cerebral angiography disclosed a large distal anterior cerebral artery aneurysm. The diagnosis was mycotic aneurysm based on the morphological features and associated endocarditis. The aneurysm and the parent artery were successfully occluded by endovascular embolization. High-dose antibiotic therapy in the following 6 weeks resulted in resolution of the infectious endocarditis. Early exclusion of ruptured mycotic aneurysm is mandatory because of the high risk of rerupture. Endovascular treatment is an effective alternative for mycotic aneurysms, especially if the patient’s general condition is poor. Parent artery occlusion can be safely tolerated if the aneurysm is located distally.