Thirty-nine premature infants, 29 of whom received human milk (HMG) and 10 of whom received formula only (FG), were enrolled in a study examining the effect of human milk on cognitive and motor development. Infants were assessed at 3, 7, and 12 months corrected ages; the Peabody Picture Vocabulary Test was administered to their mothers. HMG infants had higher motor scores than FG infants at 3 months (48 +/- 20 vs 35 +/- 12, P = .05) and 12 months (63 +/- 20 vs 46 +/- 15, P < .05) and higher cognitive scores at 12 months corrected age (101 +/- 11 vs 90 +/- 9, P < .05). HMG infants had higher scores (motor R2 = 0.2, cognitive R2 = 0.3; P < .05) adjusting for oxygen requirement and maternal vocabulary score. Human milk is associated with improved development of premature infants at 3 and 12 months corrected age in this sample.