Moyamoya disease is a unique cerebrovascular disease characterized by narrowing of the terminal portion of internal carotid arteries and circle of Willis, with consequent development of a network of collateral vessels in response to brain ischemia. Moyamoya vascular pattern can be idiopathic (Moyamoya disease), is more likely to occur in individuals of Asian ascent and in the pediatric age, or is associated with other diseases (Moyamoya syndrome).We present two cases of stroke in young adults, where workup revealed Moyamoya-type vascular changes. The first case report is of a 42-year-old woman presenting with hemorrhagic stroke, with classic angiographic findings of Moyamoya disease, otherwise asymptomatic. The second case concerns a 36-year-old woman admitted with ischemic stroke; besides the typical angiographic pattern of Moyamoya, the patient was diagnosed with antiphospholipid antibody syndrome and Graves’ disease, two conditions known to be associated with this vasculopathy.These case reports illustrate the need to consider this entity in the etiological evaluation of ischemic and hemorrhagic cerebrovascular events, even in Western countries, since management and secondary prevention require specific approaches.