Deep venous insufficiency (DVI) is a chronic disease of the lower extremity venous system that can cause debilitating symptoms with serious consequences, including pain, swelling, skin ulcers, nonhealing wounds, and varicose veins. It is a complicated disorder that is often underdiagnosed. There are many causes of DVI, and depending on the etiology of the disorder, different treatment strategies can be employed. Advanced imaging techniques such as computed tomography or magnetic resonance venogram can be used to characterize different complex anatomic variants that can cause DVI. Treatments range from conservative compression stockings and oral anticoagulation to minimally invasive procedures such as percutaneous thrombolysis and stenting. Surgical venous bypass and valvuloplasty are possible in patients with refractory disease. The purpose of this chapter is to provide a general overview of common causes of DVI and different imaging techniques that can be used to determine the underlying etiology, followed by different interventional and surgical treatment options, each with a different set of advantages and disadvantages.