A 46-year-old woman developed transient ischemic attack (TIA) caused by progressive moyamoya vasculopathy in the right hemisphere. She had presented with minor cerebellar infarction due to left vertebral artery dissection 7 years prior to the onset of TIA. Initial carotid angiography at the onset of vertebral artery dissection demonstrated absence of steno-occlusive changes in the anterior circulation. During the next 7 years, she had been strictly followed up with magnetic resonance angiography every 6 months, which demonstrated the asymptomatic development of steno-occlusive change in the proximal right middle cerebral artery, finally involving the terminal internal carotid artery. Carotid angiography at the onset of TIA showed terminal internal carotid artery stenosis with abnormal vascular network at the right base of the brain, indicating a definitive diagnosis of moyamoya vasculopathy with unilateral involvement. She underwent right superficial temporal artery-middle cerebral artery anastomosis without complication one month later. TIA completely disappeared after surgery, and no cerebrovascular events occurred during the follow-up period of 6 months. De novo formation of moyamoya vasculopathy is extremely rare in adulthood. The present case demonstrated the entire temporal profile of the development of this rare entity in adulthood. The previous presentation of vertebral artery dissection before the development of moyamoya vasculopathy as well as the initiation of steno-occlusive change at the middle cerebral artery is apparently unique.