ABSTRACT:The expansion and intensification of agriculture frequently affect riparian zones, mainly in basins where agriculture is the most important activity. In countries with basins dominated by agricultural activities, land use change in riparian zones promotes water quality loss and biodiversity degradation. As a tool to prevent these environmental impacts, the delimitation of riparian zones and buffer strips is crucial. For that purpose, photo interpretation jobs and botanical studies are usually necessary. However, a digital terrain model (DTM) becomes the best alternative when the information is unavailable or the survey area is too large. This work made the first delimitation of riparian zones of the country?s water drainage network. The results obtained by using a 1-m vertical buffer in DTM allowed the delimitation of the riparian zones of Uruguay. The results indicate that of the areas identified as riparian, 62% would be authentic and that the 29% of riparian areas identified under cultivation could rise to 46% if the identification improved the identification accuracy. The results indicate the existence of 4,608,890 ha of riparian zones, of which 94,651 ha could be under cultivation.