<b><i>Introduction:</i></b> A higher prevalence of intracranial aneurysms (IAs) has been previously reported by retrospective studies in patients with thoracic aortic aneurysms (TAAs). The goal of this study was to evaluate the prevalence of IAs in a large cohort of prospectively screened patients with TAAs and identify potential risk factors. <b><i>Methods:</i></b> Patients above 18 years with TAAs who were prospectively screened for IAs using computed tomographic angiogram/magnetic resonance angiogram over a 9-year period were included in the study. Patient demographics, comorbidities, aortic, and IA locations and sizes were analyzed. Univariate analysis was performed with the χ² test for categorical variables and the Student <i>t</i> test or ANOVA for continuous variables. <b><i>Results:</i></b> Five hundred and fifty-four patients with TAAs were prospectively screened for IAs and included in the study. Thirty-one IAs were identified in 27 patients (prevalence = 4.9%). The prevalence of IAs in patients with ascending TAAs was 4.51% and in descending TAAs was 9.09%. Twenty out of 31 IAs were 2 mm in size, 6/31 were 3 mm, and 5/31 were 4 mm in size. Hypertension was associated with an increased prevalence of IAs, especially in patients with descending TAAs. <b><i>Discussion/Conclusion:</i></b> The prevalence of IAs in patients with TAAs may not be as high as described in previous retrospective studies. Our results suggest that the prevalence of IAs in patients with TAAs is similar to the general population. Study results reveal that IAs have a higher correlation to patients with descending TAAs, although not statistically significant. Hypertension was found to be a statistically significant risk factor for IAs in patients with TAAs.