Accurate diagnosis and classification of haemangiomas and vascular malformations is essential for prediction of outcome and rational therapeutic intervention. The purpose of this review is to demonstrate how radiological techniques, including projectional radiography, ultrasound and colour flow imaging, magnetic resonance imaging, and conventional venography and arteriography can aid in the diagnosis and classification of vascular malformations in children, and to guide the radiologist in the use of modern nomenclature.