A 55-year-old woman with bilateral vertebral artery (VA) aneurysms was transferred to our hospital. She suffered from a minor stroke. Magnetic resonance imaging (MRI) for the stroke incidentally revealed bilateral VA aneurysms. Due to its size, more observation was recommended, and the patient was found eager to be treated. Both side surgeries were found inappropriate because of severe lower cranial nerve disturbances. The right aneurysm involved the posterior inferior cerebellar artery (PICA) and the V4 segment was deviated to the right side. Therefore, the smaller right aneurysm was treated first with an occipital artery (OA)-PICA bypass and a V3-radial artery graft (RAG)-V4 bypass followed by proximal clipping of the PICA and the right VA. The right VA was successfully remade by RAG and the right aneurysm was not revealed on postoperative examination. By doing so, the opposite aneurysm was able to be eliminated by the parent artery occlusion even by using an interventional radiology (IVR). The V3-RAG-V4 bypass is a useful method for treating bilateral VA aneurysms. This is a new bypass which has not been reported so far to the best of our knowledge.