A field experiment was conducted during two successive seasons (2014 and 2015) in a private orchard farm, located at the 64 km on the Cairo-Alexandria Desert Road, to study the effect of different irrigation levels, irrigation methods and olive cultivars on plant growth and yield of olive trees(Olea europara, L.). Treatments were: a- three irrigation levels: 4384 m³/feddan(100%), 3740 m³/feddans (85%) and 3089 m³/feddan (70%); b- two drip irrigation methods: on-line surface irrigation and in-line sub surface irrigation and c- two olive cultivars, Picual and Manzanillo. The experiment was designed in a split-split plot with three replicates. Estimated irrigation water was calculated, using FAO method, in order to compare between applied and estimated irrigation regime. Data revealed that using 3740m³/fed irrigation level gave the highest growth and yield compared with other treatments. The Estimated irrigation water was close to applied treatment 3740 m³/fed. In-line (surface irrigation) method recorded the highest yield and oil during the two successive seasons. The oil content in fruit increased with water decrease. The Picual cultivar showed the highest oil content while, Manzanillo cultivar gave the highest yield. The interaction between the three tested factors show that the 3740m³/fed treatment with the In-line surface irrigation combined with Manzanillo cultivar was the best combined treatment. The highest WUE was found in 3089 m³/ fed. with subsurface irrigation combined with Manzanillo cultivar.