This study set out to investigate the relationships between the neutrophil-to-albumin ratio (NAR) in the early stages of aneurysmal subarachnoid hemorrhage (aSAH) and the occurrence of delayed cerebral ischemia (DCI). A total of 439 patients with aSAH were included in this retrospective study. NAR assessment was conducted on admission. The relationship between NAR and DCI was analyzed. Eighty-four patients (23.7%) experienced DCI. NAR levels were significantly higher in patients with DCI after aSAH than without DCI (median [interquartile range] 0.350 [0.274-0.406] vs. 0.240 [0.186-0.300]; P < 0.001). NAR levels were correlated with World Federation of Neurological Surgeons (WFNS) grade and modified Fisher (mFisher) grade (r= 0.505 and 0.394, respectively). NAR and mFisher grade were the independent predictors of DCI. Under receiver operating characteristic curve, NAR levels exhibited a significant discriminatory capability (area under the curve [95% confidence interval] 0.812 [0.740-0.823]; P < 0.001). The predictive power of NAR levels was similar to mFisher grade (P > 0.05). NAR, in positive correlation with the severity of hemorrhage, appears to be a novel predictive biomarker of DCI after aSAH.