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An investigation of geological conditions is always a key point for planning infrastructure constructions. Bedrock surface and rock quality must be estimated carefully in the designing process of infrastructures. A large direct-current resistivity and time-domain induced-polarization survey has been performed in Dalby, Lund Municipality, southern Sweden, with the aim of mapping lithological variations in bedrock. The geology at the site is characterised by Precambrian granitic gneisses and amphibolites, which are intensely deformed, fractured, and partly weathered. In addition, there are northwest-trending Permian dolerite dykes that are less deformed.Four 2D direct-current resistivity and time-domain induced-polarization profiles of about 1-km length have been carefully pre-processed to retrieve time-domain induced polarization responses and inverted to obtain the direct-current resistivity distribution of the subsoil and the phase of the complex conductivity using a constant-phase angle model. The joint interpretation of electrical resistivity and induced-polarization models leads to a better understanding of complex three-dimensional subsoil geometries. The results have been validated by lithological descriptions from several drillings. In addition, direct-current resistivity and time-domain induced-polarization logging has been carried out in two different boreholes, showing a good match with the results of the surface direct-current resistivity and time-domain induced-polarization profiles.The direct-current resistivity and time-domain induced-polarization methodology proved to be a suitable technique for extensively mapping weathered zones with poor geotechnical characteristics and tectonic structures, which can lead to severe problems for infrastructure construction and/or constitute risk zones for aquifer contamination.In order to provide spatially resolved variation of rock quality, the electrical resistivity tomography (ERT) method has been successfully employed in many field cases. During the construction of the Hallandsås Tunnel in southern Sweden, for example, the ERT profiles could predict challenging zones with highly fractured waterbearing or weathered unstable rock (Dahlin, Bjelm and Svensson 1999;Danielsen and Dahlin 2009). Similarly, fractured zones in bedrock have been detected with ERT in several other field cases, e.g., tunnel projects in Italy (Cavinato et al. 2006) and Norway (Ganerød et al. 2006;Rønning et al. 2014). A large-scale application of ERT to investigate bedrock geology is shown by Storz, Storz and Jacobs (2000), where the authors detected electrically conductive fault zones in the metamorphic crystalline basement.