The Global Positioning System (GPS) observations which is a component of the GlobalrnNavigation Satellite System (GNSS) is being referenced to the World Geodetic System 1984rn(WGS84) ellipsoid with geographic coordinates defined in terms of latitude, longitude andrnellipsoidal heights ( , ,â„Ž). This prevalent situation makes it difficult to apply standard forwardrntransformation equation for direct conversion of ellipsoidal heights (h) to a practical orthometricrnheight (H) within Ethiopian local geodetic reference network. In order to overcome such arnchallenge, many researchers resort to various methods of determining the geoidal undulations forrna local and national geodetic network and improving the recent New Earth Gravitational Modelrnaccuracies and its performances. This present study therefore seeks to validate the accuracy ofrnthe geoid heights derived from the Earth Gravitational Model 2008 (EGM08) in Addis Ababa.rnThe estimated geoid heights obtained by the EGM08 model were compared with 9 geometricalrngeoid heights derived from co-located GPS and orthometric heights obtained by running firstrnorder geodetic leveling with a tie to the existing Blue Nile Bench Mark(1957- 1961). Thernmethods applied include estimating the geoidal heights using the EGM08 model and a geometricrnmethod. The statistics of the differences between derived geoid heights by the geometricrnapproach and corresponding geoid heights obtained from the Earth Gravity Model (EGM08)rnsuggests an precedented accuracy (~2.27cm) of the geoid heights computed from EGM08.