Penetrating neck injury causing internal carotid artery (ICA) transection is nearly always fatal. The novel use of Onyx Liquid Embolic System (Onyx LES) for rapid hemostasis of a traumatic cervical ICA transection is reported. A patient with a gunshot wound to the face and neck underwent emergent catheter angiography which revealed contrast extravasation from the right cervical ICA consistent with traumatic transection. The ipsilateral cerebral hemisphere showed collateral blood supply from the posterior communicating artery, and ipsilateral external carotid artery anastomoses of the facial, ethmoidal and ophthalmic arteries. Rapid endovascular repair of the transected cervical ICA was performed using Onyx LES. Onyx34 was injected at a rapid rate of 1 ml/min into the right ICA. Injection was continued until cast formation completely occluded the proximal cervical ICA but preserved the external carotid artery. This method very rapidly controlled bleeding and should be considered in these cases.