Different irrigation treatments were applied to a superintensive orchard of 'Arbequina' olives ( Olea europaea L.) during three seasons (2007-2009) to examine the effect of the amount of water and the moment of irrigation in summer on the virgin olive oil (VOO) quality. A control was made (CON) with irrigation to maintain the root zone close to field capacity; two water deficit treatments were employed with irrigation at 30% of CON, either from the end of fruit drop to the end of July (DI-J) or from the end of July until the beginning of oil synthesis (DI-A); and other treatment was tested by irrigating 50% of CON in July and August (DI-JA). DI-J oils exhibited significantly higher oxidative stability, which coincided with significantly higher contents in phenol derivatives. Consequently, the selection of the moment and intensity of summer irrigation played an important role in the nutritional and sensory quality of the VOO.