<![CDATA[Background: Mothers' knowledge and attitudes play a crucial role in the success of childhood immunization programs. Insufficient understanding of the benefits and importance of immunization may negatively affect immunization uptake. Poster-based health education is one of the educational media that can be used to improve mothers' knowledge and foster positive attitudes toward immunization. Objective: This study aimed to analyze the effectiveness of poster-based health education in improving mothers' knowledge and attitudes toward immunization at Limapuluh Public Health Center, Pekanbaru City. Methods: This quantitative study employed a pre-experimental design with a one-group pretest–posttest approach. The study was conducted from February to May 2026 and involved 159 mothers with children aged 0–5 years selected using a purposive sampling technique. The intervention consisted of health education using posters containing immunization-related information. Mothers' knowledge and attitudes were assessed before and after the intervention using structured questionnaires. Data were analyzed using the Wilcoxon Signed Rank Test with a significance level of p < 0.05. Results: Before the intervention, 80.5% of respondents had poor knowledge and 95.6% had negative attitudes toward immunization. Following the intervention, the proportion of respondents with good knowledge increased to 89.9%, and all respondents (100%) demonstrated positive attitudes. The Wilcoxon Signed Rank Test revealed significant differences in knowledge (Z = −10.967; p < 0.001) and attitudes (Z = −10.953; p < 0.001) before and after the intervention. Conclusion: Poster-based health education effectively improved mothers' knowledge and attitudes toward immunization. Posters can be utilized as an educational medium to support health promotion activities in primary healthcare settings.]]>
