Purpose To report a case in which silicone oil in the eye migrated into the cerebral ventricles and the subarachnoid space. Design Observational case report. Methods A 62-year-old woman presented with proliferative diabetic retinopathy and tractive retinal detachment in her left eye. Par plana vitrectomy and injection of 5,000-centistoke-viscosity silicone oil were performed. Intraocular pressure was elevated after the operation and poorly controlled for 4 months. Eight months after the first operation, the patient felt dizzy. Computed tomography (CT), magnetic resonance imaging (MRI), and optical coherence tomography (OCT) scanning were performed. Results The CT imaging, MRI, and OCT showed silicone oils migrated into the sella cistena superioris and the cerebral ventricles. Follow-up examination was continued. Conclusion Although silicone oil migrating into the ventricles is unusual, we suggest that every patient undergoing silicone oil tamponade with poorly controlled high intraocular pressure and optic disk atrophy should be carefully evaluated.