Urban Change Detection Urban environments are among the most dynamic systems on earth. Rapid urban expansionrnnecessitates proper planning to avoid profound negative environmental and socioeconomicrnimpacts. Geographic Information Systems (GIS) and Remote Sensing technologies provide veryrnefficient tools to collect and analyse the information necessary to detect changes in urban areasrnthat conventional surveying technology can't deliver in a timely and cost effective manner. GISrnand Remote Sensing techniques were used in this work to locate and estimate the expansion ofrnurban areas in Dukem town. Rapid urban expansion has caused not only social problems, but alsornenvironmental and socioeconomic problems in the town. The results show massive urbanrnexpansions during the study period. The population dynamics are the factors that make thernpopulation of certain area to change over time. In this case in 1986 the population of the townrnwas 3736 and the built up area 43 hectare. The population was increased to 6356 in 2005 likewisernthe built up was expanded to 505.3 hectare. In 2010 the population became 25214 and the builtrnup was expanded to 1095.44 hectare. From 1986-2005, the population of the town was increasedrnby 2620 i.e. 70.13% and 2005-2010 it was 8858 i.e. 275.2%. The built up area of the town wasrnincreased by 462.3ha i.e. 1075% from 1986-2005 and it was expanded to 590.14ha i.e. 116.8%rnfrom 2005-2010.Population, nearness to Addis Ababa, and poor policy implementation are thernmajor factors that derive horizontal expansion in the town.rnKeywords: Urban expansion, Remote Sensing, GIS, Urban Change Detection