['Breast milk has been shown to be associated with greater success with regard to weaning children with intestinal failure off parenteral nutrition (PN). There are only a few studies investigating the role of breast milk in decreasing PN-associated liver disease (PNALD). The aim of our study was to determine whether breast milk is better than formula milk in preventing PNALD in infants receiving PN for >4 weeks.', 'We conducted a retrospective analysis of newborns requiring prolonged parenteral nutrition. We divided the sample into 3 different groups (exclusive breast-feeding, exclusive formula-feeding, and mixed feeding. We compared baseline characteristics, feeding profiles and liver function tests, and liver enzymes among the 3 groups.', 'Among infants receiving PN for >4 weeks, we found that infants who were fed only breast milk were significantly less likely to develop PNALD (34.6%) compared with those who were fed only formula milk (72.7%; P = 0.008). The mean maximum conjugated bilirubin (P = 0.03) and the mean maximum aspartate aminotransferase were significantly lower in the breast-fed group (P = 0.04) compared with the formula-fed group. Among the mixed-feeding group, infants who received a higher percentage of breast milk showed a significant negative correlation with the mean maximum conjugated bilirubin. (Pearson correlation -0.517, P = 0.027). The mean number of days receiving PN and the average daily lipid intake in the 2 groups was not significantly different.'] Is breast milk better than formula milk in preventing parenteral nutrition-associated liver disease in infants receiving prolonged parenteral nutrition?