Although anomalies of the inferior vena cava (IVC) are seen frequently in a clinical setting, congenital absence of the IVC (AIVC) is rare. However, anomalies of the IVC should be considered in young patients suffering from recurrent and idiopathic DVT. We report a case of DVT possibly caused by AIVC in a 27-year-old man, and discuss the clinical features, diagnosis, and treatment of this unusual entity.