Abstract. BACKGROUND: In the United States, breastfeeding initiation (BFI) is reported for 75% of all live births; however, little information is available regarding mothers affected by gestational diabetes mellitus (GDM). OBJECTIVE: To examine feeding practices and factors associated with BFI in women with GDM and their infants. METHODS: A total of 303 GDM (58 late preterm and 245 term) pregnancies were studied. Infant feeding preference was ascertained on admission to labor and delivery. Variables known to influence BFI including maternal age, smoking, obesity, racial and educational characteristics were assessed. RESULTS: On admission 188 women intended to BF, 60 intended to feed formula and 55 were undecided. None of the women who wished to feed formula and 27% of the originally undecided later initiated BF. Regardless of feeding preference 163 (54%) of all mothers initiated BF. Similar BFI rates were found for 176 Class A1 and 127 class A2 women. Logistic regression analysis showed that intention to BF was the most significant predictor of BFI. Factors associated with BFI failure included African American race, lower education, smoking, obesity and admission to NICU. Following delivery 264 (87%) infants received well baby care while 39 (13%) were admitted to the NICU. Among 188 women who intended to BF, BFI involved 81% of 160 infants receiving well baby care and 61% of the 28 admitted to the NICU. CONCLUSIONS: More than half of women with GDM, who intended to BF, initiated BF. BFI failure remains associated with race, lower education level, smoking, obesity, preference for formula feeding and admission to NICU.