The effects of salinity on growth, leaf nutrient content, water relations, gas exchange parameters and chlorophyll fluorescence were studied in six-month-old seedlings of citrus (Citrus limonia Osbeck) and rooted cuttings of olive (Olea europaea L. cv. Arbequina). Citrus and olive were grown in a greenhouse and watered with half strength Hoagland’s solution plus 0 or 50 mM NaCl for citrus, or plus 0 or 100 mM NaCl for olive. Salinity increased Cl− and Na+ content in leaves and roots in both species and reduced total plant dry mass, net photosynthetic rate and stomatal conductance. Decreased growth and gas exchange was apparently due to a toxic effect of Cl− and/or Na+ and not due to osmotic stress since both species were able to osmotically adjust to maintain pressure potential higher than in non-salinized leaves. Internal CO2 concentration in the mesophyll was not reduced in either species. Salinity decreased leaf chlorophyll a content only in citrus.