BACKGROUND Aneurysms of the posterior circulation are challenging lesions to neurosurgeons, despite improvements in microsurgical techniques and advances in skull base approaches. We present a rare case of a posterior cerebral artery (PCA)-posterior communicating artery (PcomA) junction aneurysm associated with bilateral internal carotid artery (ICA) occlusion successfully treated with an endovascular procedure. METHODS A 57-year-old female presented with sudden onset of severe headache and loss of consciousness. CT scan showed diffuse subarachnoid hemorrhage and acute hydrocephalus. The patient developed severe neurogenic pulmonary edema and shock. Although her neurogenic pulmonary edema did not resolve, she recovered from shock. However, her general condition was so critical and her vital signs so unstable, that direct surgery under general anesthesia was considered too risky. A cerebral angiogram showed complete occlusion of both internal carotid arteries without any Moyamoya vessels. A saccular aneurysm located at the right PCA-PcomA junction was seen. To obliterate the aneurysm and prevent rerupture, the patient underwent coil embolization via an endovascular approach under sedation with local anesthesia. The balloon remodeling technique was useful to prevent occlusion of parent arteries. Finally, four interlocking detachable coils (IDC) with a total length of 44 cm were used to completely obliterate the aneurysm using the balloon remodeling technique. The patient made a full recovery after treatment and the aneurysm remained obliterated 2 years after coil embolization. CONCLUSIONS We emphasize the advantages of the endovascular approach for the patient in critical condition. We believe that this is the first report of a PCA-Pcom junction aneurysm associated with bilateral ICA occlusion without moyamoya disease.