An aortic embolus of cement occurred in a 72-year-old woman after lumbar percutaneous vertebroplasty for breast cancer metastasis. A CT scan during the procedure revealed cement migration into the aorta via the lumbar artery. The cement embolus in the aorta, along with the hook-shaped cement fragment in the lumbar artery, was asymptomatic. Thereafter, a CT scan 4 months later still showed the presence of cement in the aorta and the lumbar artery at the level of the vertebroplasty. The patient is free of complaints after 4 months without anticoagulant treatment. This rare complication occurred because the collateral arterial supplies to the breast metastasis and the retrograde migration of cement during the vertebroplasty were not recognized. Proper techniques can minimize the risk of arterial embolism caused by cement during the procedure.