Deep venous obstruction (DVO) of the inferior cava system can be caused by both thrombotic and non-thrombotic causes. The post-thrombotic obstruction of the iliocaval segment, with or without the involvement of the femoro-popliteal segment, is the most frequent situation, and in 2/3 of the cases, it occurs in association with deep venous reflux. Non-thrombotic obstruction is mainly due to venous extrinsic compression, such as May-Thurner at the iliac level, oncologic disease or retroperitoneal fibrosis. Congenital anomalies are possible, even if quite rare. Disregarding the etiology, deep venous obstruction causes outflow resistance and can lead to various clinical pictures, ranging from asymptomatic cases to severe chronic venous insufficiency (CVI), even if the post-thrombotic etiology is typically associated with more severe clinical outcomes. Endovascular techniques, venoplasty and stenting and hybrid surgical techniques, in selected cases, represent the operative procedures of choice in treating outflow obstruction. These techniques can considerably improve patients’ quality of life affected by symptomatic outflow obstruction of the ilio-caval segment.