Maternal and social risk, prenatal and obstetric care, resuscitation and neonatal care in very-low-birthweight infants (VLBW) may vary with the type of referral. In 453 VLBW's (< 1500 g) admitted to our neonatal intensive care unit 1987-1992, we classified transport type as: A: No transport (n = 240), B: Maternal transport (n = 88), C: Infant transport (n = 125). Stepwise multiple discriminant function was determined for the identified factors. The risk of mortality was investigated by logistic regression analysis. In group A, mean maternal age was higher and mothers' social status lower than in groups B and C. In group B, infants were considerably smaller and less mature, but when adjusted for gestational age, suffered less frequently from RDS, obviously due to more frequent induction of lung maturation. In group C, less than half of the infants were resuscitated by a neonatologist. Infants of this group were frequently hypothermic at admission and required prolonged artificial ventilation more frequently. Total VLBW survival averaged 77%, increasing from 69 to 88% within the study period. Total rate of severe intraventricular hemorrhage was 4.8% in surviving infants. VLBW infants with different forms of referral differ in their inherent risk. After maternal transport they have less morbidity despite a higher grade of immaturity. Regionalization of perinatal care for these infants remains the greatest potential for further reduction in infant mortality.