Immunisation is the stage of prevention of infectious diseases such as ‘hepatitis, tuberculosis, polio, tetanus, diphtheria, pertussis, and measles’ Knowledge of parents, especially mothers, plays an important role in the success of immunisation programmes, where education level affects knowledge about the importance of immunisation. The following study aimed to analyse the correlation between parents' education level and knowledge in providing complete basic immunisation to children. The following quantitative approach uses a Cross Sectional design, on 88 respondents selected through Purposive Proportional Random Sampling using a questionnaire in the form of a questionnaire and obesrvasion. Data were collected through questionnaires and analysed using the Chi-Square test. The results showed a significant relationship between education level and parental knowledge in providing complete basic immunisation at Bangetayu Health Centre, Semarang City (p-value <0.05). Thus, the higher the level of education of parents, the better their knowledge in providing complete basic immunisation to children. This study highlights the importance of complete basic immunisation to prevent disease. Health offices and health centres need to improve education through counselling and information distribution. Parents' awareness plays an important role in ensuring children are fully immunised. This study is useful for parents in increasing knowledge, health centres in improving services, and researchers as a reference for further studies.