We report a case of thrombotic giant basilar-tip aneurysm after coil embolization. A 59-year-old man had been treated with coil embolization of a ruptured basilar-tip aneurysm five years earlier. The aneurysm enlarged with a thrombotic component and compressed the midbrain, presenting with bilateral oculomotor palsy and ataxia. We performed re-embolization using a vascular reconstructive device in the hope of inhibiting neovascularization in the intra-aneurysmal thrombus by isolating the residual lumen. At two-year follow-up, the aneurysm had not expanded further and symptoms had not exacerbated.