In the arid and hyper-arid regions, the urgent need of water has led to the necessaries of detailed groundwater research to provide alternative water resource. Therefore, groundwater exploration in Sahara represents a major challenge due to the scarcity of data and the prevalence of arid climate. The Sahara had climate change alternated between dry and humid during the Pleistocene Epoch which has provided opportunities for its aquifers to be recharged during the past wet climate. The current research presents a new theory that includes the linkage between palaeohydrologic setting and groundwater occurrences which can enhance the decisions related to future explorations. The theory hypothesizes that during the past humid periods, many landforms and deposits were developed as a result of the freshwater (rainfall) existing for long periods. The areas of these palaeohydrologic features (landform/deposits) are represented as potential groundwater paleo-recharge sites. Therefore, the investigation and mapping of palaeohydrologic features resulted during these paleo-humid conditions, can improve the decision for groundwater exploration. The mapping processes can be achieved through the integration between remote sensing, GIS applications and field investigations. The spectrum signature of the palaeohydrologic-related landforms and deposits can be determined through the spectral analyses processes of the satellite images as well as GPS survey during field investigation. These features include fluvial landforms, paleo-drainage systems, and sediments (e.g., tufa and playas). The verification of this theory was achieved in some areas of Egyptian deserts. Consequently, the hydrogeologists are invited to verify this theory which can save costs, time and efforts.