The main objective of this study is to assess the impact of urban expansion onrnenvironmenl. Ihe case of Debre Markos lown. II investigaled Ihe trend of urbanrnexpansion, the causes and impacts of urban expansion and jinally recommended somernpossible allernative solutions. The sludy employed various techniques of data collectionrnand analysis. The required dala were gathered Ihrough household survey, key informal7lrninterview, observation and documel7l inspection. A total of 119 respondems wererninvolved on the study by using probability (systematic sampling) and II governmentrnofficials and expel'/s by non probability sampling lechnique (purposive). Descriplive andrnnarrative were used 10 analyze the necessGlY data. Thejinding of the study was presel7ledrnby using table, jigure, maps and photographs. The jindings of the study showed that thernIrend of urban expansion increase through time and mostly foresl and cullivaled landrnhave been changed into dijJerent urban development uses such as residential, industrial,rnand commercial and other various institutions. The major causes of this expansion in thernlown are populalion growth. lack of land informal ion system (cadastres) . availabililyofrndijJerent injrasl/'llcture and topography. This expansion exerted an adverse impact onrnenvironment mainly on cultivated land, forest, wetland, grassland, WaleI' bodies andrnother. Therefore, Ihis sludy proposes thaI municipality and cily administralion of DebrernMarkos lown together with the Amhara National Regional State should develop propel'rnpolicies thaI would bring sustainable urban development.