OBJECTIVE Hemorrhagic risk is unknown in patients with moyamoya-like vessels associated with atherosclerotic intracranial cerebral artery occlusion. This study was undertaken to investigate the association between moyamoya-like vessels and cerebral microbleeds (CMBs) in patients with atherosclerotic steno-occlusive disease. METHODS The study population comprised 34 patients with steno-occlusive lesions in the intracranial cerebral artery caused by atherosclerosis. We evaluated the presence of moyamoya-like vessels at the base of the brain by cerebral angiography, and the presence of CMBs by T2*-weighted MRI. Patients were divided into 2 groups: those with and those without moyamoya-like vessels; clinical histories and the incidence of CMBs were compared between the groups. RESULTS Sixteen patients had moyamoya-like vessels. Twelve of 16 patients with moyamoya-like vessels had a history of ischemic stroke or transient ischemic attack, whereas only 1 patient had a history of symptomatic cerebral hemorrhage. The incidence of CMBs did not differ between the 2 groups (31% vs. 28%, p=0.82). The location of CMBs varied and was not associated with the site of moyamoya-like vessels. CONCLUSIONS CMBs were not associated with moyamoya-like vessels in patients with atherosclerotic cerebral artery occlusion. These patients may not have a high risk of cerebral hemorrhage.