This research is about the environmental impact of urbanization with specific emphasis on quarrying activity in eastern Addis Ababa, one of the major expansion corridors of the capital. The study aimed at conducting spatial and temporal assessment of the impact of urbanization and associated quarrying for construction materials, on the natural environment during the last two decades. Land use / land cover change detection analysis of the period 1995-2016 has been conducted by using standard Remote Sensing and GIS methods on LANDSAT images of three different years (1995, 2003, 2016). Landform change detection on selected individual quarries was conducted for the years 2006 (when quarrying expanded) and 2016 (current state) from a baseline year of 1995 when there were no any quarry activities in the area. The Landform change detection was conducted on Quick bird images and on Google Earth platform, generating decadal DEM by using kriging interpolation of cell size (spatial resolution) 1meter. The results clearly indicate that eastern Addis Ababa has undergone an extensive land use and land cover change during the last 21 years where the urbanization (built-up area) expanded by more than 4-fold, and quarrying activity by more than 10-fold, due to the shrinking of cultivated land by half and bare rangeland by nearly 3-fold, from the baseline year of 1995. Moreover, expansion of quarrying activities is clearly related to urbanization and both happen hand-in-hand, where the period between 1995 and 2003 was marked by a slight but generally perceptible change, and since then the change was dramatic. Nearly half of the area was urbanized by 2016 at the expense of rapidly shrinking cultivated and rangelands, accompanied by a 10-fold increment of quarry sites. This implies currently the quarry to built-up-area ratio is 1:4 and though the data do not allow calculating the actual year-by-year rate of expansion and shrinking, urban planning map of the city indicate that the change was exponential rather than linear, suggests that future expansion of urban centers will lead to extensive quarry activities. In addition, there has been a continuous and perceptible modification of the landform due to quarrying, which led to massive land degradation and loss of fertile land due to forced expansion of urban centers.rnKey words: Urbanization,Quarrying, Impact Assessment, Land Use/Land Cover change, Landform change, Remote Sensing data, GIS, eastern Addis Ababa