Background: The prevalence of hypertension in patients with intracranial aneurysms has been an increased concern, but it is not well understood if uncontrolled hypertension has impact on aneurysmal rupture. The aim of this study was to determine whether the risk of aneurysmal rupture is higher in uncontrolled hypertensive cohorts than in controlled hypertensive cohorts and normotensive cohorts. Methods: We retrospectively analyzed the records and angiographies of 456 patients with aneurysms who were treated at our center between June 2013 and June 2014. Three groups of patients were included in the study following the ESH-ESC (European Society of Hypertension-European Society of Cardiology) 2013 guidelines: normotensive group (n = 229), controlled hypertension group (n = 127), and uncontrolled hypertension group (n = 100). Paired comparisons of these 3 groups were analyzed with the Nemenyi test. Multivariate logistic regression analysis was used to exclude the impact of possible confounding factors. Results: The results of the univariate analysis showed that hypertension, smoking, and size of the aneurysms were significantly associated with intracranial aneurysmal rupture (P<.05). The multivariate logistic regression analysis containing clinical and aneurysmal characteristics showed that uncontrolled hypertension, smoking, and aneurysm size were statistically significant predictors of intracranial aneurysmal rupture (P<.05). The paired comparisons of 3 groups showed that the risk of rupture of intracranial aneurysms in the uncontrolled hypertension group was significantly greater than that in the normotensive group (P<.05) and in the controlled hypertension group (P<.05). Conclusions: Uncontrolled hypertension is associated with increased risk of rupture of intracranial aneurysms. Given that aneurysmal rupture is a potentially fatal-but preventable-complication, these findings are of clinical relevance. (C) 2016 National Stroke Association. Published by Elsevier Inc. All rights reserved.