A comparative study of neonatal serum bilirubin levels was done in neonates of different age groups of mothers. A total 122 healthy, new borns were selected for the study, born at Queen Mary's Hospital, Lucknow. Mothers were divided into two groups i.e. < 30 years and > 30 years of age. Samples of blood were collected thrice, first on day 1 from cord blood, 2nd and 3rd on days three and five of life from neonates by heel prick method, using small bore capillaries for blood collection, serum bilirubin estimation were done by the method of Malloy & Evelyn and Mean +/- SD were calculated. P-Value was observed between different age groups. In both the groups of mothers i.e. < 30 years and > 30 years serum bilirubin levels in their neonates raised to highly significant levels on day 3 (P-Value < 0.001) as compared to their cord blood serum bilirubin levels. On comparing serum bilirubin levels in neonates of both the maternal groups, it was observed that there is no significant difference between two groups on day of birth and day day 5 but statistically significant difference was observed on day 3 (P < 0.05), serum bilirubin levels were higher in neonates of younger age group mothers.