This paper evaluates a simple tool, the icterometer, in assessing jaundice in the newborn. The instrument consists of a perspex scale with yellow stripes of increasing intensity, numbered 1-5, alternating with transparent areas through which the infant's blanched skin colour can be seen and compared with the coloured stripes. The scale was found to be useful for more objective screening of neonatal jaundice, particularly in decreasing the number of blood samples to be taken for serum bilirubin. The present study suggests that serum bilirubin estimation can be avoided when the icterometer readings on the face are 3 or less, unless there is a rapid rise in jaundice within 24-36 h. However, a reading on the sole of even 1 is significant and requires assessment by trained staff for blood sampling and/or phototherapy. The instrument may also be useful to peripheral staff in developing countries when deciding on referral to specialist centres and to staff in specialist centres for screening cases of neonatal jaundice and decreasing the number of blood samples.