Background: Exclusive breastfeeding (EBF) is advocated by the WHO for the first 6 months. In Rwanda, the percentage of infants who are exclusively breastfed decreases from 94% among infants aged 0-1 month to 81% among those aged 4-5 months. Little is known about what influences mothers' breastfeeding practices. This study aimed to gain insights into expectant mothers' prenatal feeding intentions, the underlying reasons, actual practices after birth, and factors facilitating or impeding EBF for the first 6 months of a child's life in Muhanga District, Rwanda. Methods: This qualitative longitudinal study, conducted between December 2016 and October 2017 as part of a larger study, recruited a purposive sample of 39 pregnant women attending prenatal consultations during their last trimester in two rural health centers. Women were interviewed during pregnancy, within the first week after birth and at 4 and 6 months postpartum to explore intentions, actual practices, critical transition points, and facilitating or impeding factors. Interviews were recorded, transcribed verbatim, and analyzed thematically. Results: Of the 39 participants, 38 intended to breastfeed within the first hour after birth, and 32 intended to breastfeed exclusively for the first 6 months. In practice, 34 initiated breastfeeding within the first hour, and 12 breastfed exclusively for 6 months. Impeding factors include perceived breastmilk insufficiency, pressure from family members, past experiences, mothers' concerns over their infants' health, mothers' heavy workload, poverty and food insecurity. Factors facilitating early initiation and EBF include mothers' awareness of EBF's advantages, confidence in their breastfeeding ability, and support from health professionals and family members.