A review of neonatal mortality at the Maternity Division of the Buffalo Children's Hospital from 1948 to 1957 has been presented, with primary emphasis on the occurrence of pulmonary hyaline membrane. During this period there were 26,109 infants born alive, including 2,001 below 2,500 gm in weight, a prematurity rate of 7.7%. Using a factor to correct for dead infants not necropsied, an incidence of hyaline membrane of 39.1 per 1,000 live-born prematures and 0.7 per 1,000 live-born full-term infants was obtained. These rates are compared to those previously reported. Among singleton infants under 2,500 gm birth weight the frequency of hyaline membrane was greater for those infants born to mothers with either bleeding or toxemias as complications of pregnancy. An increased rate among premature infants delivered by cesarean section was also obtained, but this increase was limited to those pregnancies with bleeding. Infants delivered of mothers with a history of prior stillbirths had a nearly three-fold greater incidence rate of hyaline membrane than did those mothers without such history. However, mothers with previous premature births or miscarriages did not show this increase. The suggestion is advanced that hyaline membrane, and perhaps other instances of respiratory distress of the newborn, may result from a process of intrauterine asphyxia, which in many instances is manifested also by maternal bleeding.