The benefits of exclusive breastfeeding are well known for both mother and baby. Despite this, rates of exclusive breastfeeding remain low. The present study aimed to determine the factors associated with the maintenance of this type of feeding after being discharged from the hospital after childbirth. A cross-sectional study was carried out with 1200 postpartum women in Spain. Sociodemographic, obstetric, and neonatal data were collected. Odds ratios (OR) and adjusted odds ratios (aOR) with 95% confidence intervals were calculated. Early breastfeeding initiation was identified as a factor that favors breastfeeding after hospital discharge (aOR: 2.47; 95%CI: 1.77, 3.45). Other factors that favor breastfeeding after discharge included the woman feeling very supported by her partner during pregnancy, childbirth, and the puerperium (aOR: 2.54; 95%CI:1.30, 5.00) and having previously breastfed other children (aOR: 1.97; 95%CI: 1.40, 2.76). Among the factors that hindered exclusive breastfeeding after discharge were multiple or twin pregnancies (aOR: 0.31; 95%CI 0.12, 0.83), induction of labor (aOR: 0.73; 95%CI: 0.53, 0.99), admission of the newborn to the neonatal intensive care unit (NICU) (aOR: 0.31; 95%CI 0.19, 0.52), using epidural pain relief during labor (aOR: 0.41; 95%CI: 0.27, 0.64), or a preterm newborn (aOR: 0.38; 95%CI: 0.21, 0.69). For all these reasons, it is essential to promote certain practices such as the early start of breastfeeding or the induced onset of labor, among others, in order to promote the maintenance of exclusive breastfeeding beyond hospital discharge after childbirth.