Background and Purpose: The association between intracranial aneurysms (IAs) and Marfan syndrome (MFS) is controversial. We aimed to evaluate the prevalence and characteristics of IAs in patients with MFS using brain imaging and compare it with the general population. Methods: Between 2007 and 2020, 118 patients with confirmed MFS who underwent brain imaging were enrolled and classified into 2 groups; IA group versus non-IA. Demographic data were acquired from their medical records, including age, sex, comorbidities, and aortic diseases. Two readers reviewed all brain images independently regarding the presence, morphology, size, and location of IAs. All data were compared between both groups, and IA characteristics in MFS were analyzed using a database of controls with IAs. Results: The prevalence of IAs was 11.9% in patients with MFS. IA group were significantly older in age (44.6±12.1 years in IA versus 36.8±14.0 years in non-IA, P =0.039) and had female predominance (71.4% in IA versus 43.3% in non-IA, P =0.047). All IAs were unruptured, and there was no subarachnoid hemorrhage during the follow-up period (mean; 53.5±43.3 months). The mean diameter of IAs was significantly larger (4.23±1.80 mm in MFS versus 3.04±1.57 mm in control, P =0.004). IAs with MFS were frequently located in the vertebrobasilar artery (33.3% in MFS versus 2.1% in control, P =0.002) and more common in fusiform morphology (13.3% in MFS versus 1.1% in control, P =0.048). Conclusions: This large-cohort study demonstrated a high prevalence and differential features of IAs in MFS, which may support the association between IAs and MFS.