[영문]Objectives. Commercial hospital discharge packs are commonly given to new mothers at the time of newborn hospital discharge. We evaluated the relationship between exclusive breastfeeding and the receipt of commercial hospital discharge packs in a population-based sample of Oregon women who initiated breastfeeding before newborn hospital discharge. Methods. We analyzed data from the 2000 and 2001 Oregon Pregnancy Risk Assessment Monitoring System (PRAMS), a population-based survey of postpartum women (n=3895; unweighted response rate=71.6%). Results. Among women who had initiated breastfeeding, 66.8% reported having received commercial hospital discharge packs. We found that women who received these packs were more likely to exclusively breastfeed for fewer than 10 weeks than were women who had not received the packs (multivariate adjusted odds ratio=1.39; 95% confidence interval=1.05, 1.84). Conclusions. Commercial hospital discharge packs are one of several factors that influence breastfeeding duration and exclusivity. The distribution of these packs to new mothers at hospitals is part of a longstanding marketing campaign by infant formula manufacturers and implies hospital and staff endorsement of infant formula. Commercial hospital discharge pack distribution should be reconsidered in light of its negative impact on exclusive breastfeeding.