The perinatal mortality rate of twins is four to 11 times higher than that of singletons, and twins are widely reported to have more morbidity than singletons, mainly because of a higher preterm birth rate. However, it is not clear that live-born preterm birth rate. However, it is not clear that live-born preterm twins suffer greater morbidity than comparable singletons. In fact, twins have been reported to develop pulmonary maturity earlier than singletons, which might result in decreased morbidity relative to comparable preterm singletons. We conducted this retrospective review of 496 consecutive singleton and 104 twin infants weighing 500-1499 g and born alive at 24-31 weeks' gestation to determine whether pre-discharge survival and morbidity in very low birth weight (VLBW) twin infants were greater than those of comparable singletons. The mean (+/- standard deviation) gestational age of the singletons was 27.5 +/- 2.0 weeks and of the twins 27.6 +/- 2.0 weeks. There were no differences in mean gestational age, gestational age distribution, mean birth weight, birth weight distribution, gender, or maternal race between the two groups. The pre-discharge survival rate for twins (77%) was not significantly different than that of singletons (82%). There were no differences between twins and singletons in the incidences of neonatal respiratory distress syndrome (63 versus 71%), pulmonary interstitial emphysema (14 versus 16%), patent ductus arteriosus (28 versus 29%), necrotizing enterocolitis (3 versus 5%), intraventricular hemorrhage (11 versus 16%), and retinopathy of prematurity (11 versus 18%). The incidence of bronchopulmonary dysplasia was significantly less in twins (27 versus 46%; P = .001).(ABSTRACT TRUNCATED AT 250 WORDS)