Bulbar compression by vertebral artery (VA) aneurysm is extremely rare and only reported in a few cases. We report two cases with thrombosed VA aneurysm compressing medulla oblongata; one presented with bulbar apoplexy hemorrhage and the other with subarachnoid hemorrhage (SAH). A 61-year-old male (case 1) presented with consciousness disturbances, left hemiplegia, and subsequent respiratory arrest. He was subjected to controlled ventilation, and computed tomography (CT) scan showed bulbar hemorrhage. Magnetic resonance imaging (MRI) and digital subtraction angiogram (DSA) revealed fusiform right VA aneurysm with partial thrombosis and bulbar compression. Intra-aneurysmal embolization with Guglielmi detachable coils (GDCs) relieved his clinical symptom including respiratory disturbance. Three months after the onset, he remained moderately disabled. A 76-year-old male (case 2) presented with severe headache and subsequent respiratory disturbance. CT scan on admission showed subarachnoid hemorrhage with acute hydrocephalus. Ventricular drainage rapidly improved consciousness while respiratory disturbance persisted over several days. MRI and DSA suggested spontaneous thrombosis of the right VA dissection with bulbar compression. He showed gradual recovery of his respiration over a week. After ventriculo-peritoneal shunting, he was transferred with moderate disability. These results suggest that the elimination of the pulsatile effect of VA aneurysm adjacent to medulla oblongata can improve symptoms caused by aneurysm-related compression. Early diagnosis and appropriate treatment such as intra-aneurysmal embolization for ameliorating the blood flow inside the aneurysm can relieve mass effect and clinical symptoms.