Congenital malformations of the inferior vena cava (IVC) are rare and underreported. They can be a risk factor for deep venous thrombosis (DVT) as a result of inadequate venous drainage of the lower extremities through collateral circulation. The significant number of cases reported in the literature highlights their importance, warranting investigating their existence in younger individuals with idiopathic DVT of the lower extremities and pelvic veins. In this systematic review, we depict the typical presentation of IVC malformations, their management, and the management of their associated DVT.