To assess the effectiveness of mulching on the growth and yield of three olive cvs., (Aggizy shami, Kalamata and Picual) and its influence in preserving the soil moisture, a field experiment was conducted during the two growing seasons of 2015 and 2016 in Siwa oasis. Three mulching materials i.e., shale, olive pomace and palm leaves were used and compared with control (non-mulced). In regard to the varieties fruit production, Aggizy shami showed a higher yield in both seasons as compared to Kalamata and Picual. Olive pomace and shale were the most efficient mulching materials in increasing the fruit yield. and the highest increase was found in Kalamata ( 232% of  the control in the first season) when shaleused as a mulching material. Olive pomace was more effective in the second season and caused an increase in the fruit yield  of all the tested cv, and the highest increase (70.23 % more than control) was noticed in Aggaizy shami cv. . Results revealed also that Picual cv. was more resistance to water stress as compared with the other cvs, under mulching treatments, however all inltivase were highly affected by the water stress un mulched tacatment .It can be concluded that mulching is an effective way to improve the growth and yield of olive under sandy soil conditions.