We evaluated the effect of birth order on the incidence and severity of intraventricular hemorrhage in 29 sets of very low birth weight twins (1500 g or less). Intraventricular hemorrhage occurred in 55% of first-presenting twins and 62% of second-presenting twins. The incidence of minor intraventricular hemorrhage (grades I and II) was 41% for first twins and 52% for second twins, whereas the incidence of major intraventricular hemorrhage (grades III and IV) was 14 and 10%, respectively. None of these differences reached statistical significance. We conclude that birth order does not appear to have a major effect on the incidence or severity of intraventricular hemorrhage in very low birth weight twins.