Vaccination has been shown to be the most effective way of fighting disease ever, and is one of the strategies for reducing morbidity and mortality, especially among children. In the DRC, huge disparities persist in terms of vaccination coverage among children aged 12 to 23 months, which hovers around 45%.The Bandalungwa HZ has also had low coverage over the past three years, at around 65%.The aim of this study was therefore to identify the determinants of non-completion of the immunization schedule among children aged 12 to 23 months in this health zone.Strategies to improve immunization coverage in the Bandalungwa HZ included keeping vaccination cards in good condition and making them available to immunization facilities, improving the organization of immunization sessions through formative supervision, and reducing the fees charged to mothers who bring their children to immunization sessions.