This MSc thesis work entitled " Integrated Geophysical Investigation for thernEvaluation of Ground Water Resources at ''Ada'a Plain" located in Central Ethiopia,rnOromiya Regional State and bounded approximately between geographicrncoordinates of 480000E - 540000 E and 900000N - 980000N.rnMulti-disciplinary studies are currently going on at Ada'a Plain for the evaluation ofrngroundwater potential and design of pressurized irrigation development, by thernEthiopian Ministry of Water Resources. The work is being undertaken by WaterrnWorks Design and Supervision Enterprise, on consultancy basis. Preliminaryrninterpretation and conceptualization of the groundwater system of the plain havernbeen made by the consultant. One of their findings reveals that the regionalrnhydraulic gradient seams to be affected by some geologic features. One suchrnpossibility is regional scale structure(s), acting as a hydraulic barrier that impedesrnthe movement of the groundwater.rnThis integrated geophysical investigation (Vertical Electrical Soundings/VES andrnmagnetic methods), as part of a research project for MSc dissertation, was carriedrnout to verify the inferred groundwater barrier and its possible connection to thernlinear geologic structures. Moreover, it also aims at establishing the hydro-rnStratigraphy of the plain. The magnetic survey was found to be useful inrnlithologic mapping and identifying linear geologic features. On the magnetic map,rnNW-SE trending anomalies are in conformity with the anticipated groundwaterrnbarrier. However, the inferred groundwater barrier (the main target of therngeophysical survey) was not detected and mapped by the resistivity method.