This study was carried out during three successive seasons, (2013, 2014 and 2015) in a private orchard located in North Sinai governorate, Egypt. The study was conducted on 10 years old Kalamata olive trees planted at 6 X 6 m apart grown in sandy soil, under drip irrigation system and uniform in shape and received the common horticultural practices. The aim of this study was conducted to evaluate Kalamata olive trees irrigation techniques which involve two types (whole root-zone irrigation – alternate partial root-zone irrigation) and three levels of regulated deficit irrigation values based on crop evapotranspiration (irrigated with 100%, 80% and 60% of ETc). The obtained results indicate that alternate partial root-zone irrigation increased vegetative growth, number of inflorescences per shoot, number of perfect flowers, crop yield, fruit oil content and fruit quality characteristics as compared with whole root-zone irrigation technique. On the other hand, the previous parameters recorded strong correlation with the highest level of irrigation treatments (100% ETc control treatment) while, regulated deficit irrigation with 60% of ETc recorded the lowest values in these respect while 80% ETc treatment came in between. In general alternate partial root-zone irrigation technique saved at least 20% of irrigation water as compared with whole root-zone irrigation and improving water use efficiency.