The primary purpose of this study was to evaluate the accuracy of gestational age (GA) estimates by using the New Ballard Score (NBS) in newborns 24 to 27 weeks GA with accurate obstetric estimates of GA. Secondary purposes were: (1) to compare the accuracy of GA estimates derived from the NBS, the original Ballard score, and the physical items of the original Ballard score and (2) to compare these measures of GA and best obstetric estimates of GA as predictors of survival, morbidity, and hospital stay among infants <28 weeks' gestation and among very low birth weight infants in general.