Aim: The overall aim of the thesis is to create knowledge about what it means for women to initiate breastfeeding and what consequences these meanings have from an existential perspective. Approach and method: A lifeworld approach based on the epistemology of phenomenology and hermeneutics was used. Lifeworld interviews and meaningoriented analysis in accordance with the chosen lifeworld approach were performed. A synthesis and a philosophical analysis were carried out that facilitates an understanding of the existential meaning of initial breastfeeding and its consequences as a whole. Main findings: Initiating breastfeeding, when it functions well, entails an existential challenge, a movement from a bodily performance to an embodied relationship with the infant and with oneself as a mother. When breastfeeding is experienced as being severely difficult, it entails an existential lostness as a mother, forcing her into a constant fight with herself, the infant, and others in order to find her way into motherhood. Severe breastfeeding difficulties can evoke existential vulnerability, forcing the mother to continue breastfeeding despite the difficulties, while hoping to be confirmed as a good mother; a fear of breastfeeding may be a consequence. Existential security is a necessary condition for continued breastfeeding whilst insecurity and fear of breastfeeding can lead to ceased attempts to breastfeed when experiencing severe initial difficulties. Initial breastfeeding and motherhood are intertwined in a way that affects the woman’s existence as a mother. Conclusions: Initial breastfeeding is a complex phenomenon that is more than just a biological adaptation or a cultural issue; it touches on and evokes existential aspects of being a woman and a mother. Though anchored in both biology and culture, breastfeeding cannot be reduced to one or the other: it is both. There is a struggle between biology and culture that has existential consequences for women’s experiences of breastfeeding, the breastfeeding decision, and the women’s existence as a mother. There is a need for health professionals to look beyond the statistics of breastfeeding and consider the existential dimensions of breastfeeding-as-lived when encountering mothers wanting to breastfeed