Background: Immunization remains one of the most important public health interventions and a cost-effective strategy to reduce both the morbidity and mortality associated with infectious diseases. Over two million deaths are delayed through immunization each year worldwide. Aims: This study sought to identify specific factors associated with immunization coverage in order to advance improved intervention, policies/strategies therefore raising overall immunization coverage. Materials and Methods: A cross-sectional study was conducted among a total of 198 children aged 12-23 months at Urban Health and Training Centre (UHTC), Era's Lucknow Medical College, Lucknow, over a period of 6 months i.e., from July 2012-December 2012. Data were collected, compiled and tabulated using Microsoft Excel and analyzed using SPSS 17.0 version. Results: A total of 198 children of age 12-23 months were included in this study, of which 74.7% of children were fully immunized, 11.1% were partially immunized and 14.1% were not immunized at all. The most common reason for partial or non-immunization was family problems (24%) of the respondents followed by lack of knowledge of immunization (20%), and fear of side effects (16%). The odds of risk of partial/non-immunization in illiterate women is 5.78 more than the graduate women (P = 0.039). Conclusions: Although in the present study, majority of the children were immunized, it is still not up to the mark. We have to make it 100%, so that we can reduce mortality due to vaccine-preventable diseases. Increasing awareness and reducing fear of side effects of immunization among parents through health education, counseling, etc. can increase the percentage of immunized children.