Secondary chronic venous disorders (CVD) usually follow an episode of acute deep venous thrombosis (DVT). Most occluded venous segments recanalize over the first 6 to 12 months after an episode of acute DVT, leading to chronic luminal changes and a combination of partial obstruction and reflux. Such morphological changes produce venous hypertension with the highest levels of ambulatory venous pressure occurring in patients with combined outflow obstruction and distal reflux. The clinical manifestations of secondary CVD, including pain, venous claudication, edema, skin changes, and ulceration are commonly referred to as the post-thrombotic syndrome. Such sequelae are best avoided by early and aggressive treatment of proximal DVT. The diagnostic evaluation of secondary CVD is similar to primary CVD and is based upon duplex ultrasound. However, the definition of hemodynamically significant venous stenosis remains obscure and there are no reliable tests to confirm the presence of such lesions. Diagnosis depends more on anatomic rather than hemodynamic criteria, and IVUS is superior to venography in estimating the morphological degree and extent of iliac vein stenosis. The fundamental role of compression in the treatment of CVD is well recognized. Compliance with compression is essential to heal ulcers and minimize recurrence. The efficacy of various adjuncts to ulcer treatment, including complex wound dressings and medications have been variable. Although superficial venous surgery has not been demonstrated to improve ulcer healing rates, it does decrease ulcer recurrence. Deep venous valve reconstruction is performed in only a few specialized centers, and the results are better for primary than for secondary CVD. Treatment of incompetent perforating veins remains controversial. Although artificial venous valves are promising, most early experimental models have failed. With respect to venous obstruction, iliocaval angioplasty and stenting has emerged as the primary treatment for proximal iliofemoral venous obstruction with surgical bypass assuming a secondary role.