Basilar artery occlusion developed in a 34 year old woman 2 months after adopting unusual neck postures during yoga practice. On angiography, her basilar artery was filled with intraluminal clot while the vertebral arteries were normal. We postulate that a severe reduction in blood flow and possibly an intimal tear triggered thrombosis of the vertebral artery and that the final stroke mechanism was artery-to-artery embolism.