Abstract: Atopic dermatititis (AD) in Indonesia is increasing every year, occupying the first position of the top 10 skin diseases in children. Faktor genetik dan lingkungan berperan dalam DA, menyebabkan kelainan pada sistem kekebalan tubuh dan lapisan kulit epidermis, yang berujung pada hipersensitivitas tipe 2. Padangsidimpuan City has a fairly high incidence rate of dermatitis (27.5%) and a low Pure Participation Rate (APM). Based on this background, given the high prevalence of children, along with low APM, the researcher wanted to conduct his research in the city. This study aims to determine the relationship between the level of knowledge, attitude, and behavior of mothers and the incidence of atopic dermatitis at the Sadabuan Health Center, Padangsidimpuan City, North Sumatra. This research method is observational analytical, where dependent and independent variables are measured, then the data obtained will be analyzed to find the relationship between variables with a cross-sectional approach, where the variables being studied are measured at the same time. The results of the analysis showed the relationship between the mother's level of knowledge and the incidence of AD (p-value: 1.000), the mother's attitude with the incidence of AD (p-value: 0.620), and the mother's behavior with the incidence of AD (p-value: 0.591). There was no relationship between the mother's knowledge, attitude, and behavior on the incidence of atopic dermatitis in children at the Sadabuan Health Center, Padangsidimpuan City.