Context: Modified Ballard Score is used for assessment of gestational age of a neonate. It is most accurate when done between first 12-20 hours of life, but its validity is known only up to 7th day of life and not beyond it. Aim: To assess the validity of Modified Ballard Score for assessment of gestational age after 7th day of life. Materials and method: The study was conducted in the NICU of Katihar Medical College, Katihar. It is an observational study carried over a period of 3 months, in which 44 neonates were examined in accordance to the physical and neuromuscular criteria of Modified Ballard Score on days 1,3,7 and 10 of life and the result was then compared to the gestational age as calculated from a first trimester ultrasonography report or mother’s LMP, whichever was available. Result: Out of 44 subjects, the gestational age from Modified Ballard Score on day 10th of life was accurate in accordance to mother’s LMP or first trimester ultrasonography report in 24. Statistical analysis done using IBM SPSS Statistics 24 model revealed a p value of 0.000. Hence, it can be concluded that modified Ballard score is valid after 7 days of life. Conclusion: Since the Modified Ballard Score is observed to be significant on day 10th of life in most of the cases according to the study, therefore, it can be used to assess gestational age of a neonate after 7 days of life.