Objectives: To examine feeding efficiency and correlates of feeding behaviors in breastfeeding as compared with boute-feeding VLBW infants at 35 weeks corrected age (CA, postmenstrual plus chronologic age). Study design: In all, 105 singleton VLBW infants underwent a standardized feeding observation, of whom 35 were observed breastfeeding and 70 bottle-feeding. Intake, efficiency, and feeding behaviors were compared, and effects of infant and maternal factors were examined. Results: Breastfeeding as compared with bottle-feeding infants took in smaller volumes (median 6.5 vs 30.5 ml, p<0.001), fed less efficiently (median 0.6 vs 2.2 ml/min, p<0.001), and spent less time with sucking bursts (mean 33 vs 55%, p<0.001). For breastfed infants, birth and neonatal factors and prior maternal breastfeeding experience were not associated with feeding efficiency or behaviors. Conclusion: Feeding performance of breastfeeding compared with bottle-feeding VLBW infants at 35 weeks CA is worrisome, and lactation intervention is needed for discharge planning. © 2004 Nature Publishing Group All rights reserved.