The cause of thrombosis is often unknown but is universally ascribed to part of Virchow's triad: stasis, hypercoagulability, and intimal injury. Venous thromboembolic disease is a common and costly medical problem, with iliofemoral deep vein thrombosis (IFDVT) being a less common but often underestimated presentation of this condition. Treatment options for deep vein thrombosis (DVT) have expanded in recent years and now include systemic anticoagulation, thrombolytic therapy, and surgery. Several studies have shown the efficacy of catheter-directed thrombolytic therapy in resolution of IFDVT. There is also growing evidence that early lysis is more likely to preserve valve function leading to a decrease in the incidence of postthrombotic syndrome, which is a known long-term complication of DVT and IFDVT. The following case report describes a patient, without malignancy, who had an atraumatic iliac and femoral DVT and illustrates the diagnostic considerations and therapy of a patient with iliofemoral DVT.