Jaundice is the most common clinical symptom in the neonatal period. Free serum bilirubin levels during the first days after birth are higher than at any point later in life. Breastfeeding is associated with both increased risk and severity of jaundice. Early-onset breastfeeding jaundice is primarily a result of insufficient caloric supply and resolves gradually with the normalisation of lactation. Late-onset type, i.e. breast milk jaundice, develops after 4–7 days of life in otherwise healthy neonates and is mainly associated with the presence of an unknown factor in breast milk, which increases the enterohepatic reabsorption of bilirubin. Breast milk (late-onset) jaundice is the most common cause of persistent jaundice due to increased unconjugated bilirubin. Elevated conjugated bilirubin always indicates a pathological process and requires urgent diagnosis extension. It was believed until recently that breast milk jaundice is a mild condition, which never leads to central nervous system damage. This, however, is not entirely certain in the light of currently available scientific research; therefore it is necessary to monitor bilirubin levels. Since breast milk jaundice is a diagnosis of exclusion, it is usually preceded by differential diagnosis. In the case of breast milk jaundice, serum bilirubin levels will return to normal by 12–14 weeks of life. In the case of newborns/infants in good condition, who develop properly and gain weight systematically, supporting parents in effective breastfeeding, monitoring and regular check-ups of the child are recommended. Breast milk jaundice is not a contraindication to prophylactic vaccination.