The basement rocks of Ethiopia were traditionally described as a system of regional aquiclude.rnThis attribution ignores regional differences in aquifer properties, structure and functioning. Inrncontrast, this work presents how the interactions of evolutionary and modern geologicalrnprocesses determine aquifer development and hydrogeological characteristics of the basementrnterrain of Ethiopia. It specifically addresses the role of geomorphic history (deep weatheringrnand stripping) in affecting aquifer genesis and their control on vertical and spatialrnheterogeneity. In addition, the study provides field evidences for existing literature basedrnweathering-stripping model previously developed for the country. Detailed examination ofrngeological, hydrological and hydrogeological evidences enabled the understanding of therncauses of regional variation in aquifer properties. The aquifers exhibit noticeable regionalrndifferences. Thus, conceptual hydrogeological model depicting three coherent categories ofrnaquifers are developed: (a) in western basement terrain, aquifer is relatively extensive in thernthick weathered mantle over fractured bedrocks of low to high-grade metamorphic rocks. Highrngroundwater storage but low hydraulic conductivity characterizes this aquifer. (b) in thernnorthern, groundwater occurs in fractures and discontinuities in bedrocks toward the surfacernand tectonically induced relatively deeper fracture zones. These aquifers have high hydraulicrnpermeability but low storage capacity. (c) in the Borena lowlands of southern basement region,rngroundwater occurs in wadi beds, fractures, and preferentially weathered mantles. Thernorientations of wadi beds follow regional fractures, which control groundwater flow regime andrnenhance preferential weathering of bedrocks. Aquifers are of intermediate type with regard tornhydraulic properties. The variations in low-flow indices and shapes of flow duration curves ofrnstreams manifest contrast in bulk storage capacity and hydraulic conductivity of catchments inrnthe three basement regions. This contrast has been used as evidences for characterization ofrnaquifers.The implication of these regional differences on groundwater exploration andrnexploitation has been the subject of this study.