Abstract: The study area is located in the Adrar region of Northern Mauritania covering the main watersheds of Atar district (Wadi Seguelli) and Aoujeft district (Wadi Labiodh). The agricultural activities of palm trees and gardening under palm trees are the main economical activities in this region. The farmers depend directly on the water points at the Wadis alluviums for irrigation and water supply. Meanwhile, this sensitive resources are under the influences of sever natural conditions and increasing demand for agricultural use as well as for domestic use. All these have made the development of water resources one of the difficult challenges in this region. This study aims at identifying suitable sites for Water Harvesting (WH) in the arid zone of Northern Mauritania (oasis area) using Landsat imagery and GIS technology. The combinations of different thematic layers; prepared from remote sensing images and ancillary data, such as land cover, geology, slope, drainage, geomorphology and lineament, using weighted overlay technique permit an effective way for monitoring and planning natural resources. The suitability analysis results reflect the limitations of suitable areas, which are concentrated at the Wadis beds along the valley zone with 1.4% of excellent to high suitability.