Objective: To determine the incidence of bronchopulmonary dysplasia, its risk factors and resource utilization in a large South American population of very low birth weight infants. Methods: Prospectively collected data in infants weighing 500 to 1,500 g born in 16 NEOCOSUR Network centers from 10/2000 through 12/2003. Multivariate relative risk and 95% confidence intervals were estimated by Poisson regression with robust error variance to find factors that affected the risk of bronchopulmonary dysplasia. Results: 1,825 very low birth weight infants survivors were analyzed. Mean birth weight and gestational age were1085±279 g and 29±3 weeks respectively. Bronchopulmonary dysplasia incidence averaged 24.4% and survival without bronchopulmonary dysplasia augmented with increasing gestational age. A higher birth weight and gestational age and a female gender all decreased the risk for bronchopulmonary dysplasia. Factors that independently increased that risk were surfactant requirement, mechanical ventilation, airleak, patent ductus arteriosus, late onset sepsis and necrotizing enterocolitis. Bronchopulmonary dysplasia infants had more days of hospitalization (91±27 vs. 51±19), of mechanical ventilation (19±20 vs. 4±7) and oxygen therapy (72±30 vs. 8±14) in comparison with non BPD infants. Conclusions: Bronchopulmonary dysplasia incidence was 24.4% in a large South American population and is related to greater resource utilization. Population and is related to greater resource utilization. Risk factors for bronchopulmonary dysplasia in this study were: surfactant requirement, mechanical ventilation, airleak, patent ductus arteriosus, late onset sepsis and necrotizing enterocolitis. These studies may provide useful information in the design of effective preventive perinatal strategies. Copyright © 2006 by Sociedade Brasileira de Pediatria.