The influence of several clinical factors on the cephalocaudal progression of neonatal jaundice was investigated in 377 newborns admitted to the neonatal intensive care unit for various reasons. Multiple regression analysis showed that, beyond the relationship to the plasma bilirubin concentration, the cephalocaudal color gradient was significantly, negatively related to gestational and postnatal age. Furthermore, the cephalocaudal progression of jaundice seemed more extended in females compared to males. The results are in agreement with a theory explaining that the cephalocaudal color gradient is due to conformational changes in the newly formed bilirubin albumin complexes.