Background: This research aimed to assess the level of knowledge and attitudinal disposition regarding childhood immunization among nursing mothers attending postnatal clinics in selected health facilities in Ondo town, Nigeria. Methodology: A cross-sectional survey design was employed in this study; a total number of three hundred and eighty-six (386) respondents participated in this study. A multistage sampling technique was used to select eleven (11) groups from Ondo West and Ondo East LGA. Systematic random sampling was then employed to select three (3) groups from Ondo West and Ondo East LGA, in which all the health centers in the three groups were used for this study. A structured and validated instrument was used for data collection and was administered to the participants at the health facilities using direct contact approach. Analysis of the data was done using descriptive statistics and correlation which was fixed at 0.05 significance level. Results: The study found that nursing mothers aged 31-40 years represented the highest proportion (35.5%) of attendees at postnatal clinics, while 16.8% were adolescents. The majority were married (71.5%) and had attained tertiary education (41.7%). Knowledge about immunization was generally high, with 90.7% having heard of immunization, though only 64.2% acknowledged potential side effects like convulsions. The mean knowledge score was 12.63 ± 4.23, indicating moderate knowledge. Regarding attitudes, 72% had positive attitudes toward immunization. Age and education were significantly correlated with both knowledge (p = 0.002) and attitudes (p = 0.000).  

Conclusion: The study concluded that strategic behavioral communication needs to be developed to dispel fears of side reactions and provide targeted information that will boost and maintain immunization coverage in the study area