Confusion in terminology and classification means one of the most serious problems in congenital vascular malformations (CVM). Syndromes like Klippel-Trenaunay's and F.P. Weber syndrome have been described before angiography had been developed. Above all noninvasive and new imaging modalities (such as ultrasound, computed tomography and magnetic resonance imaging) angiography is the method of choice for classification and decision in finding an adequate therapy. Arteriography above all has to define and localize arteriovenous fistulae and its hemodynamics whereas phlebography must demonstrate the malformative outflow, its extent and degree of primary or secondary functional decompensation. Lymphography is only used rarely in detection of veno-lymphatic and lympho-cystic components of the CVM.