Saudi Arabia is enriched by many geothermal resources that are located along the western coastal part of the Red Sea, in the form of a number of hots prings and many volcanic eruptions.Wadi Al-Lith is considered one of the most promising geothermal targets that encounter many hot springs with a good surface temperature up to 95 1C. This paper aims mainly to evaluate the geothermal potential of the main hot spring at Wadi Al-Lith area (Ain Al Harrah).The available remote sensing images are analyzed and a number of2Delectricresistivityprofiles areinterpretedtodelineatethesurfacegeologicallineaments and the subsurface structural elements that control the movement of the thermal water. It is found that the main surface lineaments are structurally oriented along NNE–SSW and NE–SW direction swith a frequency percentage of 52% and an average lineament length of 835 m. Furthermore the subsurface structural elements, as inferred from the interpretation of the geophysical 2D electric profiles, have assumed the same directions beside the NW–SE direction. The characteristics of thermal water of the hot spring are indicated through analyzing the major and minor elements of some collected water samples.Geo-thermometers are applied to estimate,subsurface temperature,heat flow and discharge enthalpy. These parameters are found to be 136 1C, 183 mW/M2 and 219 kJ/kg,respectively. An estimate of the geothermal reserve using the volumetric method,gave total stored heat energy of 1.713
1017 J (rock and fluid) and a geothermal reserve potential of 26.99 MWt. It appears from our research that the estimated energy is quite enough for operating a medium scale power plant that utilizes low boiling point fluid (Kalina Cycle) for limited electricity production,beside other low-temperature applications(district heating,green houses and medical therapy).