<![CDATA[DPT immunization, which protects against diphtheria, pertussis, and tetanus, was an important preventive measure against infectious diseases among infants and young children. However, some mothers remain hesitant to have their children receive DPT immunization due to insufficient knowledge regarding Adverse Events Following Immunization (AEFI). Adequate knowledge of AEFI was considered important in increasing maternal confidence in following the recommended immunization schedule. Objective: This study aimed to determine the relationship between maternal knowledge of AEFI and DPT immunization administration at Serasi Primary Clinic, Medan, in 2026. Method; A cross-sectional approach was employed in this study. The study population consisted of all mothers who visited Serasi Primary Clinic, Medan, to have their children receive DPT immunisation, consisting of 41 mothers. Total sampling was used; therefore, the entire population of 41 mothers was included as the study sample. Data on maternal knowledge were collected using a questionnaire, while information regarding DPT immunization administration was obtained through observation of the Maternal and Child Health (MCH) book. Result;The results of the Chi-square test showed a p-value of 0.000 (p < 0.05), indicating a statistically significant relationship between maternal knowledge of AEFI and DPT immunization administration at Serasi Primary Clinic, Medan, in 2026. Conclusion; Mothers with better knowledge of AEFI were more likely to have their children receive DPT immunization according to the recommended schedule. Therefore, healthcare professionals were encouraged to strengthen educational interventions concerning AEFI in order to increase maternal understanding and improve DPT immunization coverage.]]>
