We report a case of bilateral thalamic infarcts with no apparent cause other than unilateral partial occlusion of the P1 segment of the posterior cerebral artery caused by Guglielmi detachable coils in a basilar tip aneurysm. This case demonstrates that bilateral thalamic infarctions can result from a unilateral posterior cerebral artery stenosis or occlusion, and does not necessarily imply bilateral posterior cerebral artery abnormality.