Introduction: North Sumatra province has the highest prevalence of diarrhea in children under-five in Indonesia. The incidence of diarrhea in children under-five is related to individual and environmental risk factors that interact with each other within the spatial space. Objective: To find the risk factors, spatial patterns, and priority areas of intervention for the case of diarrhea in children under-five in North Sumatra. Method: The research design is ecological. Risk factors for diarrhea in children under five are determined by Pearson correlation. Global Moran was used to determine the spatial dependency of the incidence of diarrhea in children under-five, while LISA (local indicators of spatial association) was used to identify priority areas for intervention. Result: There is a significant positive relationship between the incidence of diarrhea in children under-five and the percentage of households without their own latrines. The spatial pattern of diarrhea incidence in toddlers in North Sumatra is clustered. There are seven main priority areas of intervention divided into two clusters. The first cluster is located in the middle towards the east, the second cluster is located in the south. Conclusion: Efforts to prevent diarrhea in children under-five are carried out by building family latrines and providing education about the importance of owning a latrines, especially for residents who line in priority areas of intervention. © 2023 MPPKI. All rights reserved.