Vascular anomalies is a complex group of diseases, extremely variable in type, site, extension, and symptoms. This great variability is the cause of confusion and incorrect approach. In order to approach correctly these diseases, a clear classification is necessary. In the past, different efforts have been made to get a complete and easy to understand classification: three periods can be recognized. The descriptive period is characterized by efforts to describe abnormal cases which were not really understood. The anatomopathological period began with Rudolf Virchof who introduced the term “angioma” and recognized different types of “angiomas” according to the vessels involved. The main progress was the evolution to the third step, the “vessel type based classification”, which is today the best and mainly accepted classification created by a group of experts from ISSVA, the International Society for the Study of Vascular Anomalies. Other classifications are related to some specific aspects of these diseases, like clinical symptoms, a-v malformations, and venous malformations.