Background: Little data exists on the impact of metabolic acidosis in aneurysmal subarachnoid hemorrhage (aSAH). Given its detrimental effects in critically ill patients, we inquired whether in patients with aSAH, metabolic acidosis (bicarbonate <22mmol/L) was associated with an increased risk of worse outcomes at 3 months (mRS >2). Methods: We performed a retrospective analysis of the CONSCIOUS-1 randomized control trial dataset including all patients who had at least three bicarbonate levels drawn. Bivariate and multivariate logistic regression models were used to assess for independent relationship between metabolic acidosis and functional outcome at 3 months. Delayed cerebral ischemia (DCI) was assessed for potential effect modification. Results: Three hundred and nineteen patients were included in our analysis. There was no difference in the proportion of poor outcome between those with or without metabolic acidosis on bivariate analysis (OR=1.022, p=0.949). However, amongst individuals who develop DCI, there was increased odds of unfavorable outcome when patients developed metabolic acidosis (OR=7.588, p=0.023). Conclusions: Individuals who develop delayed cerebral ischemia may benefit from having their bicarbonate level carefully monitored. More studies are needed to determine how the development of metabolic acidosis can be mitigated, and whether its prevention leads to improved outcomes.