Objective: Vitamin D deficiency has been associated with increased risk and adverse outcomes in many clinical settings including cardiovascular disease, stroke, and critically ill patients. Therefore we aimed to determine whether vitamin D deficiency had any effect in aneurysmal subarachnoid hemorrhage (aSAH) clinical outcomes. Methods: A retrospective record review was conducted in a tertiary community hospital in Puerto Rico. Adult patients admitted to the neurosurgical intensive care unit with a diagnosis of aSAH from January 2013 to July 2014, who had a 25-hydroxyvitamin-D level drawn, were included. Results: A total of 40 patients were admitted with a diagnosis of aSAH, and 33 met the inclusion criteria. Overall, 81% of patients were vitamin D deficient or insufficient. Subjects were grouped into those with vitamin D deficiency (n = 13) and those without (n = 20). Except for a larger prevalence of coronary artery disease, all other baseline parameters were similar. No significant difference in hospital mortality was observed (P = 0.676). The percentage of vasospasms, vasopressor use, hydrocephalus, and infections was also similar. An increase in length of neurosurgical intensive care unit stay and respiratory failure was observed in the vitamin D-deficient group, but it was not statistically significant. Conclusion: A high prevalence of vitamin D deficiency and insufficiency was found among patients admitted with a diagnosis of aSAH in this cohort. Despite this no difference in clinical outcomes was observed in patients when compared by vitamin D group. Further studies are needed to assess potential effects of vitamin D deficiency in this patient population including long term follow-up after discharge.