Pseudoaneurysms are relatively common in the adult population because of the high volume of procedures requiring large bore arterial access. This experience has allowed adult caregivers to develop simple maneuvers to treat pseudoaneurysms such as ultrasound-guided thrombin injection. However, because of the extremely low volume of pseudoaneurysms seen by pediatric caregivers, this modality has not been well documented in the pediatric population. Here, we present a case of a 13-year-old female who had a stab wound to her left leg and subsequently developed a pseudoaneurysm of the anterior tibial artery that was successfully treated with ultrasound-guided thrombin injection.