One of the chronic nutrition problems in Indonesia is stunting, which is a risk marker for bad child development. This study aims to determine the relationship between drinking water sources, drinking water treatment and sewage management to the incidence of stunting in two-year-old children in Mamuju Regency. This type of research is observational analytic using cross-sectional study. Samples of this study were all mothers of two-year-old children who live in Mamuju Regency. The total sample in this study were 191 respondents. The sampling technique by using the Proportional Random Sampling technique. Data were analyzed by bivariate analysis using chi-square test to assess the relationship between independent variables (drinking water sources, drinking water treatment and sewage management) and dependent variables (stunting). The results showed that there was a relationship between drinking water sources (PR 1,394, 95% CI, 0,970-2,003, p=0,042), drinking water treatment (PR 1,332, 95% CI, 1,048-1,693, p=0,038) and sewage management (PR 2,743, 95% CI, 1,265-5,948, p=0,000) with the incidence of stunting in 2-year-old children in Mamuju Regency. Therefore, it is expected that the public will consume drinking water from protected sources and treat drinking water before consumption for the prevention of water-borne diseases. In addition, it is also necessary to implement waste management that is safe for health and the environment. Keywords: Children, Stunting, Drinking Water, Sewage.