Color coded duplex sonography has definitive advantages over conventional duplex sonography for investigation of lower limb vessels. It contributes significantly to the non-invasive evaluation of peripheral aneurysms and complications associated with arterial puncture. After arterial graft surgery it is an effective imaging method to check bypass patency and evaluate suspected complications. Furthermore, color coded duplex sonography is sufficiently accurate to definitely diagnose lower extremity DVT, when not technically compromised. Postthrombotic vascular changes and clot alteration under anticoagulant treatment can be demonstrated with high sensitivity.