Cerebral palsy is the end result of a variety of insults to the fetal and neonatal brain. Today with improved diagnostic techniques relatively few cases of cerebral palsy should be attributed to an idiopathic cause. This edition of The Clinics in Perinatology explores the many known causes of cerebral palsy including prematurity, asphyxia, birth defects, metabolic disorders, birth trauma, growth restriction, multiple gestation, and perinatal infections. Reviews of current diagnostic testing modalities such as placental pathology, neuro-imaging, and metabolic testing are provided.