We report a case with a pseudoaneurysm of the common carotid artery treated by carotid aneurysmectomy.A 34-year-old male was admitted with a swelling on the left side of his neck. A duplex ultrasound showed a 2.5×1.5×1.5cm pseudoaneurysm of the left common carotid artery, 1cm caudal to the bifurcation. Twelve hours later the pseudoaneurysm had increased and an acute aneurysmectomy was performed. An 8mm externally supported expanded polytetrafluoroethylene (ePTFE) graft was interpositioned. The patient was discharged 1 week after the surgery and 6 months after the operation he had recovered completely from a paresis of the left vocal cord. The reason for the pseudoaneurysm formation remains unclear as no bacterial, iatrogenic or traumatically aetiology was found.