Background and Objective: Vaccination is a cost-effective intervention to prevent major illness that contribute to child mortality in the country. Increase in parental knowledge about vaccination will lead to increase in vaccination rates of children. Urban slums constitute one of the high-risk areas of vaccine preventable diseases. The main objective of the study was to determine the mother's knowledge towards childhood immunization and to assess the reasons for incomplete immunization. Material and Methods: A community based, cross-sectional study was conducted in the urban slums of Bhopal city, India. Out of the enlisted slums, 5 slums were chosen. House to house survey was done. After obtaining oral consent, information regarding knowledge, attitude and practices was collected by using a proforma. Results: A total of 300 children in the age group of 0 to 24 months were included in the study. 154 Children out of 300 (51.33%) were fully immunized, 67 (22.33%) were partially immunized and 79 (26.33%) were unimmunized. Majority of the mothers (83.6%) showed positive attitude towards getting their child. About 15.6%participants had the misconception of stopping the immunization if it caused side effects Majority 60% of mothers were unaware about the age-related vaccination. The main reason for partial and non-immunization was found to be lack of information poor infrastructure. Conclusion: Immunization coverage in the urban slums of Bhopal is still short compared to national standards. A lack of information and motivation among the parents is the main reason for this dismal scenario, that needs to be rectified at the earliest