We aim to determine the cerebrospinal fluid levels of high mobility group box 1 in subarachnoid hemorrhage patients and to investigate the involvement of the receptor for advanced glycation end products and high mobility group box 1 in the pathogenesis of post-subarachnoid hemorrhage neuronal death. The study included 40 patients (mean age, 59 ± 19 years) with Fisher's grade ≥ III aneurysmal subarachnoid hemorrhage. Cerebrospinal fluid was collected on the seventh day post-hemorrhage. Receptor for advanced glycation end products expression was examined in rat brain tissue following subarachnoid hemorrhage and in cultured neurons exposed to post-subarachnoid hemorrhage cerebrospinal fluid. Therapeutic effects of the recombinant soluble form of RAGE on subarachnoid hemorrhage models were also investigated. The results indicated that a higher level of cerebrospinal fluid high mobility group box 1 was independently associated with unfavorable outcome at three months post-subarachnoid hemorrhage (OR = 1.061, 95% CI: 1.005–1.121). Expression of RAGE increased in post-subarachnoid hemorrhage rat brain cells and in cultured neuron with stimulation of post-subarachnoid hemorrhage cerebrospinal fluid. Administration of recombinant soluble form of RAGE significantly reduced the number of positive TUNEL staining cells in subarachnoid hemorrhage rat and improved cell viability in post-subarachnoid hemorrhage cerebrospinal fluid-treated cultured neurons. Thus, the level of cerebrospinal fluid high mobility group box 1 can be a prognostic indicator for patients with Fisher's grade ≥ III aneurysmal subarachnoid hemorrhage and that treatment with soluble form of RAGE is a novel approach for subarachnoid hemorrhage.