Background: Acute subarachnoid hemorrhage (SAH) is a neurological emergency with significant potential for long-term morbidity and mortality. Nesfatin-1 is a polypeptide which is found in various regions of the brain that play role in the feeding and metabolic regulation. Objective: So this study aimed to investigate if nesfatin-1 levels in patients with SAH, could be used as a marker for the severity and prognosis. Method: Forty-eight consecutive patients (except those excluded) admitted to the emergency service of our hospital and hospitalized at our clinic with the diagnosis of aneurysmal SAH between 2011 and 2013 were included in the study and followed up for six months for outcome. The control group consisted of 48 healthy individuals of similar age and gender. Results: During the 6-month follow-up, 7 of 48 patients died and 16 (33.3%) patients had poor Glasgow Outcome Score (GOS) scores. In the study group, themean nesfatin-1 level was significantly higher than the control group (7.36 +/- 2.5 pg/ml and 4.29 +/- 2.02 pg/ml, respectively; p < 0.01). The mean nesfatin-1 level was 11.58 +/- 0.87 pg/ml in the non-survival group and 6.64 +/- 1.89 pg/ml in the survival group. Furthermore, it was 10.22 +/- 1.42 pg/ml in patients with poor outcome in terms of GOS and 5.93 +/- 1.46 pg/ml in those with good outcome. The nesfatin-1 levels significantly increased with worsening of GOS, the World Federation of Neurological Surgeons grading system, and Fisher scores and increasing plasma C-reactive protein levels (p < 0.01 for all). Conclusion: The present study is the first that shows the mortality/poor outcome of the SAH with assessing serum nesfatin-1 levels. So levels of nesfatin-1 might be useful in SAH management.