Background: Acute respiratory infections (ARI) are the leading cause of morbidity and mortality in children under the age of five worldwide. The incidence of ARI in Kampung Galuga, Binong in 2018 is as much 1,313 cases. A factor influencing the incidence of ARI in infants is the lack of knowledge of the mother. Objective: This study was conducted to determine the relationship of maternal knowledge about ARI with maternal behavior in the prevention of ARI in Kampung Galuga, Binong. Research Methods: The research method uses quantitative correlational with a cross-sectional approach. The study population is all mothers who have children one to five years in Kampung Galuga, Binong, with a sample of 40 respondents. The sampling technique used was accidental sampling. The study was conducted in May-June 2020. Data analysis used univariate and bivariate analysis with the Somers'd test. Results: The results of this study showed that most mothers had sufficient knowledge about ARI (52.5%) and good behavior in prevention (57.5%). The results showed there was no relationship between maternal knowledge about ARI with maternal behavior in the prevention of ARI with P-value= 0.128 (P<0.05). Recommendation: Researchers can then search for existing variables with qualitative research methods to provide an overview of matters relating to the prevention of ARI under-fives. Puskesmas can work together with village officials in conducting health education and prevention of ARI to residents.