Reduction in cerebral blood flow (CBF), one of the major metrics for cerebral perfusion, is associated with many brain disorders. Therefore, early characterization of CBF prior to occurrence of symptoms is essential for prevention of cerebral ischemic events. We hypothesized that large artery atherosclerosis might be a potential indicator for decline in cerebral perfusion. The aim of this study was to investigate the relationship between large artery atherosclerosis and CBF in asymptomatic adults. A total of 134 asymptomatic subjects (mean age, 56.2 +/- 12.8 years; 54 males) were recruited and underwent magnetic resonance (MR) imaging for brain and intracranial and extracranial carotid arteries. Presence or absence of cerebrovascular atherosclerosis was determined on MR vessel wall images. The CBF was measured with pseudo-continuous arterial spin labeling (pCASL) imaging. The CBF values in internal carotid artery (ICA) (37.2 +/- 5.8 vs. 39.0 +/- 4.9 ml/100 g/min, P = 0.049) and vertebrobasilar artery (VA-BA) territories (42.0 +/- 6.8 vs. 44.8 +/- 7.0 ml/100 g/min, P = 0.023) were significantly reduced in subjects with cerebrovascular plaque compared to those without. Presence of cerebrovascular plaque was significantly associated with CBF of VA-BA territory before (odds ratio, 2.89; 95% confidence interval, 1.37-6.08; P = 0.005) and after adjusted for confounding factors including age, gender, body-mass-index, diabetes, systolic blood pressure, hyperlipidemia and history of cardiovascular disease (odds ratio, 2.76; 95% confidence interval, 1.18-6.46; P = 0.019). In conclusion, presence of cerebrovascular atherosclerosis is independently associated with reduction in CBF measured by pCASL in asymptomatic adults, suggesting that cerebrovascular large artery atherosclerosis might be an effective indicator for impairment of cerebral microcirculation hemodynamics.