Twenty seven healthy newborn infants who developed hyperbilirubinaemia during the first week of life were investigated by daily test feeds between the second and sixth days of life. Nutritive sucking was assessed by measurement of rate, duration and pressure of sucking and by clinical observation. Milk consumption, duration and pressure of sucking all showed a significant increase during the period of study. Sucking rate did not vary with age. Significant correlation of sucking time and sucking pressure with milk intake were observed. Serum bilirubin levels showed no correlation with milk consumption on each day of the study or with the pooled data of feeding parameters when compared independently of post-natal age. Hyperbilirubinaemia was significantly correlated with the infants who appeared disinterested in feeds when assessed by clinical observations of apparent hunger and alertness at the onset of the test feed. However, milk intake was not impaired in these infants.