Background: Cystic Fibrosis Foundation guidelines recommend human milk (HM) as the ideal source of nutrition for children with CF (cwCF). Despite known pulmonary and nutritional benefits, fewer cwCF ever receive HM compared to the general population. Early nutrition choices are preference-sensitive, yet little is known about the factors that impede or sustain HM feeding among parents of cwCF. Objectives: Explore perceptions and experiences of mothers of cwCF who initiated HM feeding. Methods: Mothers of cwCF aged ≤10 years completed audio-taped, semi-structured interviews describing their experiences with HM feeding. Interviews were transcribed and two researchers independently coded the transcripts and conducted content and thematic analysis using an inductive approach. Results: Participants included 28 mothers who initiated HM feeding. Major themes included 1) the impact of a CF diagnosis on HM feeding plans 2) CF-specific challenges to HM feeding 3) mixed perceptions of the CF team’s support for HM feeding and of the role of formula in CF nutritional care and 4) the benefit of lactation consultants as part of the CF care team. Conclusion: Many parents prioritize HM for their cwCF given the well-established health benefits. However, CF-specific barriers to HM feeding are common and nutritional challenges necessitating fortification add additional barriers to sustained HM feeding efforts. While HM may improve long-term pulmonary outcomes, our findings demonstrate the need for personalized support for mothers desiring to HM feed to facilitate shared decision-making around options to optimize early nutritional status among cwCF.