Aneurysms of the posterior spinal artery (PSA) are rare lesions. Isolated PSA aneurysms, not in the setting of a high-flow environment, are even more rare. In the few reported cases, these lesions have been predominantly resected or observed. The authors report an isolated pseudoaneurysm of the PSA at the T-11 level presenting with subarachnoid hemorrhage. The patient underwent successful endovascular obliteration. To the authors' knowledge, this is the first report of an endovascular repair of an isolated PSA aneurysm.