Objective: To evaluate the safety and efficacy of endovascular embolization of ruptured cerebral aneurysms during acute stage of subarachnoid hemorrhage (SAH). Methods: Results in 40 consecutive patients (14men, 26women; mean age, 50.9years; range, 34-72 years) with acutely ruptured cerebral aneurysms who were treated with endovascular coil embolization were evaluated. The mean length of angiographic follow-up was 8.8 months (range, 3-18 months). Results: Forty-four aneurysms were treated endovascularly in 40 patients. The technical success rate was 97.7% (43 of 44). There were 2 (4.5%) cases of intraprocedural bleeding, which caused 1 death. There was 1 (2.5%) case of rebleeding causing death within 24 hours after endovascular embolization, and clinical outcome was good for 92.5% patients had Glasgow Outcome Scale scores of 4 or 5 at the end of the study period. Conclusion: Endovascular coil embolization is a safe method for cerebral aneurysms that are difficult to treat surgically during acute SAH. Intraprocedural bleeding is the main adverse event associated with this treatment. Delayed rebleeding is possible after endovascular treatment.