Hospital practices and early maternal return to work are associated with breastfeeding duration; however, research has not documented the long-term effects of many hospital policies or the effect of early return to work on breastfeeding outcomes of WIC participants. This study investigated the impact of in-hospital breastfeeding, receipt of a formula discharge pack, and maternal return to work on the long-term breastfeeding outcomes of 4,725 WIC participants in Los Angeles County, California. Multivariate logistic regression analyses were used to assess determinants of exclusive breastfeeding at 6 months and breastfeeding at 6, 12, and 24 months. In-hospital initiation of breastfeeding, exclusive breastfeeding in the hospital, receipt of a formula discharge pack, and maternal return to work before 3 months were all significantly associated with breastfeeding outcomes after controlling for known confounders. Mothers who exclusively breastfed in the hospital were eight times as likely as mothers who did not breastfeed in the hospital to reach the AAP recommendation of breastfeeding for 12 months or longer (P < .01). Only 6.9% of the sample reported exclusively breastfeeding for 6 months or more, and just one-third reported any breastfeeding at 12 months. Nine in ten respondents received a formula discharge pack in the hospital. Mothers who received a discharge pack were half as likely to exclusively breastfeed at 6 months as those who did not receive one (P < .01). Medical providers should educate, encourage, and support WIC mothers to breastfeed in the hospital and refrain from giving formula discharge packs.