In this study, 500 newborns with an icterus of less than 2 weeks duration and a weighf of 1500 grams or more , and who had not been exposed to phofotterapy or an exchanoe transfusion were evaluated and their chincal icterus and the concentr ation of tofal and direet bilieef biliudin in the serum ealclated Between the yellow coloraion of the skin and serum bilirudin concentrafion , a signifcant corredation (r=0.808) is ted not refafal to age, sex weeghf of birth (excepf for weights less than isoo grams which was not waluated) and the speed of on increase in biliuhin con eentraion . More over, an appropriate model to predicf the concenfration of serum bilirubin on the basis of yellow coloration of the skin has been forwarded.