The objective of the present study was to assess central aortic pressure and wave reflection in children and adolescents at different birth weights. Two hundred nineteen healthy children (126 girls), from 7 to 18 years of age (mean, 11.3 years) and born at term after a normotensive pregnancy, were included. The subjects were divided according to birth weight: <2.5 kg, from 2.5 to 2.999 kg, from 3.0 to 3.5 kg, and >3.5 kg. Pressure waveforms were recorded from the radial artery of the wrist, and the waveform data were then processed by the SphygmoCor radial/aortic transform software module to produce the estimated aortic pressure waveform. Augmentation index, an estimate of the pulse wave reflection, was significantly higher in children with the lowest birth weights compared with the other birth weight groups. In a multiple regression analysis, short stature, low heart rate, female gender, and lower birth weight had independent significant inverse correlations to the augmentation index when adjusted for diastolic blood pressure (R2=0.21). In summary, the results showed a relatively aged phenotype of large-vessel function in the children with the lowest birth weights. These early alterations may be amplified throughout life and may contribute to the increased cardiovascular risk associated with low birth weight.