We investigated the relationship between the levels of granulocyte elastase alpha 1-proteinase inhibitor complex (E-alpha 1-PI) in plasma and severe intraventricular hemorrhage (IVH) in very low birthweight infants. The concentrations of E-alpha 1-PI and the ratio of the concentrations of E-alpha 1-PI to polymorphonuclear leucocyte counts within 24 h of birth in infants with severe IVH were significantly higher compared with those in infants without severe IVH. E-alpha 1-PI seems to be a useful indicator of IVH.