Childbirth and neonatal periods have a great emotional effect on families and are considered as a new experience in life. Aim of the paper is to assess the knowledge regarding immunization of infant among fathers in selected hospitals of Pune city. The objective is: (1) To assess the knowledge regarding immunization of Infant among Fathers. (2)To associate the findings with selected demographic variables. Material and methods: A non-experimental research design was adopted to conduct the study. A tool of 100 samples was selected by using non-probability convenient sampling technique. The study instrument was a structured questionnaire. Section I consist of demographic variables of fathers. Section II consists knowledge structured questionnaire to assess the knowledge of fathers regarding immunization of infant. The tool was content validated by expert and translated into a local language which was again validated. The reliability value is 0.78 which is highly reliable. Majority of fathers are in the age of 26 to 30 years. Majority of fathers are from the Hindu religion and are belongs with joint family. Maximum fathers are working in private sector. Majority fathers having average knowledge.