OBJECTIVE: The aim of the present study was to investigate the prevalence and predictors of combined >50% iliocaval venous obstruction (ICVO) and superficial venous reflux (SVR) in patients with chronic venous insufficiency (CVI) with a healed (C5) or an active (C6) venous leg ulcer (VLU). METHODS: We conducted a retrospective review of prospectively collected data from patients with CVI with CEAP (Clinical, Etiology, Anatomy, Pathophysiology) class C5 (healed ulcer) or C6 (active ulcer) with SVR who had been treated at our institution from February 2017 to January 2018. The demographic, clinical, and surgical data and duplex ultrasound and computed tomography venography findings were collected. We used OsiriX MD, version 2.9, software (Pixmeo SARL, Bernex, Switzerland) to measure the vein diameter via multiplanar reconstruction. The prevalence of combined >50% ICVO and SVR was evaluated, and univariate and multivariate analyses were performed to identify the independent predictors of >50% ICVO in patients with CVI and SVR. RESULTS: A total of 79 limbs from 67 patients were enrolled. The mean age was 59.82 ± 12.86 years, the mean body mass index was 28.68 ± 6.41 kg/m, and 41.8% were men. The prevalence of >50% ICVO in the patients with SVR was 31.6%. Univariate analysis showed a history of deep vein thrombosis (DVT) in the affected leg (P = .001), a VLU in the left leg (P = .033), a history of a recurrent VLU (P = .038), and reversed flow in the superficial epigastric vein (P = .004) were significantly associated with >50% ICVO in patients with CVI and SVR. Multivariate analysis revealed a history of DVT in the affected leg (adjusted odds ratio [aOR], 8.31; 95% confidence interval [CI], 2.29-30.19; P = .001), a VLU in the left leg (aOR, 3.95; 95% CI, 1.18-13.19; P = .026), and a history of a recurrent VLU (aOR, 3.08; 95% CI, 1.02-9.32; P = .047) to be independently associated with combined >50% ICVO and SVR in patients with CVI. CONCLUSIONS: The prevalence of combined >50% ICVO and SVR in patients with CVI and CEAP C5 or C6 was 31.6%. The independent predictors of combined >50% ICVO and SVR in those with CVI were a history of DVT in the affected leg, a VLU in the left leg, and recurrent VLUs.