Evapotranspiration components and some water stress related variables were followed during Summer 1994, in a peach orchard, with the aim of quantifying the water consumption of the orchard and analysing the usefulness of those variables for irrigation scheduling purposes. The experiment was conducted near Setúbal (50 km south-east from Lisbon), on a sandy soil. The relative contributions of transpiration (T) and soil evaporation (Es) to total evapotranspiration (ET) are described, as well as, the crop coefficient (Kc), along the two months. Results are also presented for the evolution of leaf water potential, stomatal resistance, relative transpiration, daily trunk shrinkage and soil water content, during periods of complete water shortage. The relationships between relative transpiration, available water in soil and the cumulated transpiration since last irrigation are analysed, as possible tools for irrigation scheduling models.