Rapid urbanization activities put significant pressure on catchments around the globe as they are also associated with changes in land use and land cover. Despite the availability of satellite images, information about their applicability for assessing the trend of land use and land cover in highly urbanizing catchments is still scarce. This study used GIS-based techniques to investigate land use and land cover changes in the Msimbazi River catchment in Dar es Salaam, Tanzania. The Landsat images of the selected study years (1998, 2009, and 2018) were processed in the ArcGIS software. The land use classes were grouped into five groups: water bodies, forests, low-intensity, medium-intensity, and high-intensity development. The study observed a significant change in land use and land cover in the Msimbazi catchment from 1998 to 2018, with an estimated 40.54% decrease in lowintensity developed areas and a 15.95% increase in high-intensity developed areas defined with 80 to 100% impervious cover. Approximately 61.67% of the catchment's total area was covered by low-intensity developed areas in 1998. The low-intensity developed areas, however, rapidly reduced from 21.13% of the total area in 2009 to only 16.82% in 2018. On the other hand, the proportion of land surface occupied by medium-intensity developed regions has been generally increasing over time. Additionally, it was noted that the trend of high-intensity development has been increasing; in 1998, the coverage of this type of development was approximately 3.82%, but by 2009, it had increased to 13.42%, and by 2018, it had reached 19.77%. In addition, the extent of development and the impervious surface cover was observed to be increasing downstream approaching the Indian Ocean coast. Citations: Mkilima, T. (2022). Mapping of Land Use Changes in Urban Catchments. A Case of Msimbazi Catchment in Dar es Salaam, Tanzania.