The present study was conducted on a group of Iranian mothers with icteric newborn in order to identify any wrong knowledge and improper practices related to the neonatal jaundice. Such an estimate of knowledge and practices of mothers may be required for implementing the educational programs on which the preventive measures of kernicterus are principally thought to be depended. Between June 2004 and February 2007, 1666 mothers with icteric newborn hospitalized at a single center were enrolled. A questionnaire was used to assess the participants' knowledge and practice of neonatal jaundice. A knowledge score was calculated based on the responses. The mean knowledge score was 3.38 +/- 1.23 (out of 6). About 77% of the mothers had moderate-to-high level of knowledge of neonatal jaundice. Approximately one-third of the mothers consulted a physician within 24 h of appearance of jaundice and 13.8% declared that they waited and managed their children with traditional remedies until they sought medical advices. Furthermore, 32.2% of the mothers discontinued feeding their icteric offspring with colored foods and colostrums. Hence, 42.8% of the mothers acted weakly with regard to their icteric offspring. The health care workers were the participants' major source of information about neonatal jaundice. The present study determined a fairly adequate knowledge of Iranian mothers about the neonatal jaundice with incomparable level of related practices. The findings of this study should be considered seriously by the local health centers and the medical professionals to provide consistent information about jaundice and its causes for the parents.