Background: The current infant mortality rate for India in 2020 is 29.848 deaths per 1000 live births. A package of newborn care exists in India and Primi mothers should be aware of specific vital aspects of newborn care which can have an impact on neonatal mortality and morbidity rate. Objective: To assess the effectiveness of a comprehensive newborn care package program on knowledge and practice regarding newborn care among Primi post natal mothers. Methodology: A pre-experimental design was conducted. A non-probability purposive sampling technique was used to select 41 Primi postnatal mothers who fulfilled the inclusion criteria. Selfstructured questionnaires were used to assess the knowledge regarding newborn care and an observation checklist was used to assess the practice regarding newborn care. Results: Descriptive and inferential statistics were used to analyze the data. Studies revealed that the majority of mothers 19(46.3%) were from the age group of 27-30 years. In pretest, the majority of mothers 28(68.29%) had inadequate knowledge, whereas in posttest 18(43.90%) mothers had adequate knowledge. In practice regarding mummification, breastfeeding and hand washing, the majority of mothers, 33(80.48%), 35(85.36%) and 39(95.12%) had adequate practice regarding newborn care respectively. In the correlation coefficient, the calculated ‘r’ value (0.52) shows a positive correlation between knowledge and practice at p(0.000)<0.001 level, which showed that the neonatal care package program helps in improving knowledge and practice among Primi post-natal mothers. Conclusion: The adequate knowledge and practice showed that there was a significant improvement of knowledge and practice after administration of the neonatal care package program among Primi post natal mothers.