The two cases, one carotid-cavernous fistula and one giant aneurysm of internal carotid artery, treated with Debrun's latex detachable balloon catheter technique are reported. Case 1 was a 50-year-old man who had proptosis, chemosis and 3rd nerve palsy in his right eye. His cerebral angiography showed typical traumatic carotid-cavernous fistula. Following complete radiologic and neurologic examination, the fistulous opening was successfully occluded with preservation of the internal carotid artery using latex detachable balloon. Immediately after occlusion of the fistula the clinical symptoms were markedly improved. Only transient facial pain occurred as a complication. Case 2 was a 21-year-old woman who had a dizziness and left facial nerve palsy. The cerebral angiography showed a giant aneurysm at the petrous portion of left internal carotid artery. The patient tolerated occlusion of the left carotid artery. The left internal carotid artery was completely occluded with 3 detachable balloons. The patient had no complications during 9 days follow-up. The procedures and complications of detachable balloon catheter technique will be described and discussed.