Interruption or hypoplasia of the inferior vena cava, with associated azygos continuation, is an uncommon congenital vascular malformation (Ellis et al, Comput Radiol 1986;10:15-22). Although this anomaly causes venous stasis, few patients present with history of deep vein thrombosis (DVT). The exact role of coexisting thrombophilic gene mutations, also heterozygotic, is far from being completely understood. However, in these cases, because of a probable additive effect, treatment of complications and careful prophylaxis for recurrent DVT are recommended lifelong. The authors report a case of inferior vena cava interruption with azygos continuation in a 30-year-old woman who presented with a history of recurrent lower limb DVT. In addition, heterozygosis for the H1299R polymorphism of the factor V gene (Factor V HR2), for the C677T polymorphism of the methylenetetrahydrofolate reductase gene (MTHFR C677T) and for the 4G/5G polymorphism of the plasminogen activator inhibitor-1 gene (PAI-1 4G/5G) was found in DNA analyses.