A review of five investigations is presented, dealing with the incidence of pre- and perinatal complications among samples of childhood schizophrenics, as compared to normal control samples. All of the studies indicate a significant association between complications of pregnancy and childhood psychosis, but they fail to reveal a relationship between low birth weight, by itself, and the development of psychosis in childhood. Some of the studies indicate that a history of previous reproductive loss, severe postnatal illness, and birth complications may also be significant variables. Problems of sampling and methodology, as well as implications of these findings, are briefly discussed.