Basic immunization is the provision of early immunization to achieve immunity levels above the protective threshold. The basic immunizations that are required for infants aged 0-9 months are BCG, Measles, DPT, Hepatitis B, and Polio. Basic immunization functions to provide protection and reduce the risk of morbidity and mortality with diseases that can be prevented by immunization (Mulyanti, 2016). This study aims to determine knowledge, education, attitudes in mothers related to basic infant immunization in the working area of ​​PuskesmasTambusai Utara, Riau. Immunization is a way to actively or passively increase a person's immunity with a disease, so that if one day he is exposed to the disease he will not suffer from the disease. Types of immunization consist of active and passive immunizations. Active immunization is an immunization that stimulates the body to actively produce specific immunity against a disease. The independent variables in this study are knowledge, education and attitude, the dependent variable is basic infant immunization. This type of research is cross-sectional, the sample in this study was obtained using total sampling. Data analysis was performed by bivariate analysis using the chi square test. The results showed that of 27 mothers with good knowledge there were 27 people (96.4%) who gave complete basic immunization to babies. Meanwhile, out of 8 mothers with sufficient knowledge, 1 (3.5%) gave complete immunization to babies and 7 people (100%) did not provide complete immunization to babies. There is a relationship between knowledge, education and attitudes of mothers with the provision of basic immunization for infants in the working area of the Tambusai Utara Health Center in Riau in 2020 (p = 0.000).