Angiogenesis, the growth of new blood vessels, is an essential process occurring both in health and in disease. This process is regulated by a complex interaction of angiogenesis-stimulating growth factors and by angiogenesis inhibitors. This review describes the underlying mechanisms and principles of angiogenesis, and summarizes its role in several pediatric topics as the retinopathy of prematurity, aseptic osteonecrosis, hemangiomas and vascular malformations and its role in pediatric malignancies.