Objective: Although it is well known that smoking is a risk factor for subarachnoid hemorrhage, the association between smoking and unruptured intracranial aneurysms remains unclear. The aim of the present study was to investigate whether smoking status was associated with unruptured intracranial aneurysms among Japanese brain health check-up examinees.Materials and Methods: We conducted a cross-sectional study of 1,496 adults (aged 26–90 years) undergoing brain health check-ups at a single community medical support hospital in Akita, Japan between 2009 and 2013. In Japan, people can discretionarily undergo a brain health check-up for early detection of unruptured intracranial aneurysms or subarachnoid hemorrhages. Participants responded to a questionnaire on lifestyle, such as smoking status, and were classified into three groups: never, former, and current smoker. The evaluation of unruptured intracranial aneurysms detected by magnetic resonance angiography was performed by an expert physician. Multiple logistic regression models were used to estimate the odds ratio for unruptured intracranial aneurysms. We performed statistical analyses by age, sex, and family history of stroke.Results: The number of participants with unruptured intracranial aneurysms was 43 (2.9%). The mean age (standard deviation) and proportion of males was 55.8 (9.5) years and 53.3%, respectively. The adjusted odds ratios (95% confidence intervals) for unruptured intracranial aneurysms of 1.21 (0.48–3.08) among former smokers and 2.88 (1.10–7.50) among current smokers were compared to those of never smokers (p-trend = 0.041). After stratifying by age, sex, and family history of stroke, no interactions were found.Conclusion: This cross-sectional study conducted in Japan showed that smoking was positively associated with unruptured intracranial aneurysms among brain health check-up examinees.