Immunization is a process by which people get immunity against infectious diseases. Objective: To assess the Knowledge, Attitude and Practice Factors of parents regarding immunization. Methods: A descriptive cross sectional research study design was used to assess “knowledge, attitude and practice factors of parents regarding immunization” conducted among 134 people at EPI center of Jinnah Hospital, Lahore. The population was targeted through convenient sampling technique. Results: The overall result of study shown that parents having good knowledge (70.1%), positive attitude (83.6%) and good practice factors (59%), toward infant Immunization. Parent of child had good knowledge and positive attitude about infant immunization. Immunization was significantly associated with people education. The Cronbach alpha, Bartlett’s and KMO values have been checked to ensure the validity and reliability in our context. The values showed that positive and significant results and tool were considered as reliable and valid for performing statistical analysis. Conclusions: The findings of this study showed that the most of the participants have good knowledge and positive attitude towards the immunization, but still the one third population having the poor knowledge and negative attitude toward immunization due to the lack of knowledge and religious beliefs about the immunization were reported as the major barriers towards the immunization. The study results showed that health related practice factors were appropriate as health care worker who were daily at EPI center and give significant guidance to the parents.