The effect of urbanization to streams is summarized in the Urban Stream Syndrome (USS). The symptoms of the USS are often attributed to the discharge of large volumes of stormwater into streams causing changes to hydrology, increased nutrient and contaminant concentrations and biodiversity loss. However, the USS was developed based on evidence from high-income economies in the Global North and the extent to which it applies to low- and mid-income economies of the Global South is unclear. Urban expansion in the Global South is often marked by large volumes of untreated sewage being discharged into urban streams. In this presentation we will explore the role of untreated sewage to the USS in the Global South, specifically in Latin America. We reviewed studies that consider the effect of untreated sewage on urban streams in Latin America and assessed whether sewage has the potential to affect urban streams in similar ways as stormwater. We found an overall lack of empirical studies addressing the effect of sewage to urban streams in Latin America. Despite that, existing evidence suggest untreated sewage can be as important as stormwater in driving the USS. We assert that to support effective management and conservation of urban streams in Latin America, untreated sewage pollution needs to be explicitly considered in the application of the USS.