Treatment of blood blister-like aneurysms of the internal carotid artery (ICA) is difficult because the wall of the aneurysm is fragile and there is a high risk of rebleeding. There has been no consensus on the best way to treat these aneurysms. A 32-year-old woman presented with subarachnoid hemorrhage (SAH) caused by a ruptured blood blister-like aneurysm of the ICA. The site of the aneursym was clipped. Although angiography 1week after the operation showed that the aneurysm had been treated successfully, 3 weeks after the initial operation, the aneurysm was found to have recurred to the distal side. In a second operation, the aneurysm was successfully treated by trapping with a high-flow bypass. This case shows that clipping of the rupture site can be insufficient to treat blood blister-like aneurysm of the ICA causing SAH, even if the aneurysm seems to have resolved in follow-up angiographic studies. Trapping of the ICA with a bypass, if necessary a high-flow bypass, is recommended.