Background: The under-five age group is a group with ARI patients with high morbidity and mortality rates. From january to june 2019, the wonorejo health center in Samarinda city recorded 1055 cases of ARI in all age groups, with the highest position being the toddler age group Objectives: The purpose of this study was to determine the density of occupancy with ARI disease in toddlers aged 6-59months in the working area of the Wonorejo Health Center, Samarinda City. Research Metodes: This type of research is a quantitative research with a cross sectional design. The population in this study were all toddlers aged 6-59 months who visited and registered (recorded in the child regiter book) at the Wonorejo Health Center in September 2019 as many as 110 toddlers. Based on the calculation of slovin samples as many as 86 people. Data analysii using Chi-Square test Findings: The results showed that there was a relationship between residential density and ARI in children under five in the Wonorejo Health Center working area, Samarinda city Conclusion: The public is expected to pay attention to the number of people in one room, preferably two adults and one toddler with a minimum area of 9m2, because if in one house there is one family member whose ARI can infect others, epecially if sleeeping in one room which is less than 9m2 and there is no ventilation or ventilation of less than 10% of the floor area