A 15-year-old female presented to the emergency department of a level 1 trauma centreafter being involved in a high-speed motor vehicle accident. The patient underwent a contrast-enhanced CT scan of the abdomen and pelvis obtained with a 60-70 s delay as part of the institution's polytrauma protocol. The CT scan demonstrated multiple hepatic lacerations and a filling defect in the suprahepatic inferior vena cava adjacent to the cavoatrial junction. Inferior vena cava thrombus secondary to blunt abdominal trauma is extremely rare, and to our knowledge, this is the first reported case of acute thrombus diagnosed by CT at the time of initial injury. There is limited literature on management of this entity. Possible treatments range from conservative approaches to anticoagulation and placement of IVC filters.