Many lactating mothers participate in the workforce and have their infants cared for outside of their home, yet little is known about their child care providers' (CCPs') support of breastfeeding. This study examines the association between CCPs' breastfeeding support as reported by mothers at 3 months and mother's breastfeeding at 6 months. Infant Feeding Practices Study II, a longitudinal study, followed mothers of infants via mail questionnaires almost monthly from late pregnancy throughout the first year. This study consisted of 183 mothers who breastfed and had their infant in child care at 3 months and answered 5 questions regarding CCPs' supports. Total number of CCPs' support was a summary of responses to individual items and categorized into 3 levels (0-2, 3-4, or 5 total supports). Multiple logistic regressions examined how each breastfeeding support and total number were associated with breastfeeding at 6 months. Breastfeeding at 6 months was significantly associated with CCP support to feed expressed breast milk (AOR = 4.55; 95% CI = 1.09, 18.95) and allow mothers to breastfeed at the child care place before or after work (AOR = 6.23; 95% CI = 1.33, 29.16). Compared to mothers who reported fewer than 3 total supports, mothers who reported 5 supports were 3 times as likely to be breastfeeding at 6 months (AOR = 3.00, 95% CI = 1.11, 8.13). Our findings suggest that CCPs' breastfeeding support at 3 months, particularly feeding expressed breast milk and allowing mothers to breastfeed before or after work, may help mothers maintain breastfeeding at 6 months.