Objective: Turning of infants during phototherapy for hyperbilirubinemia is practiced in many nurseries. However, there is little research evidence in support of this practice. This study examined the effect of turning on serum total bilirubin concentration and on the duration of phototherapy. Study Design: We first conducted a pilot study in term infants requiring phototherapy using transcutaneous bilirubinometry in order to determine the time required to clear the skin of bilirubin. This "blanching time" was found to be approximately 150 minutes. We then conducted a randomized study comparing turning the baby during phototherapy with care in the supine position only. Results: Thirty term infants were enrolled in the study (turned - 14; supine - 16). No differences were found between the groups in baseline data, such as birth weight, gestational age, age at start of phototherapy, or type of feeds. Infants in the supine group showed a significantly larger drop in serum total bilirubin concentration and required a shorter duration of phototherapy. Conclusion: We conclude that infants should be nursed supine during phototherapy. Based on these results, we propose a modification to the traditional model of bilirubin kinetics during phototherapy.