Successful management of saline water could have significant potential for agricultural development in many areas, particularly in water-scarce regions. To date, the effect of salinity on leek (Allium porrum L.) yield and growth parameters has not been studied in detail. Therefore, the present study was designed to evaluate the effects of different levels of irrigation-water salinity (0.38, 1, 2, 3, 4, 5 and 7 dS m(-1)) on leek yield, evapotranspiration and drainage-water salinity. The experiment was conducted in pots using a randomized plot design with 4 replications. Increases in irrigation-water salinity caused decreases in plant height; stem diameter; leaf, stem and root fresh weights; and leaf, stem and root dry weights. Water-use efficiency, leaf area and chlorophyll content also decreased with increases in irrigation-water salinity; however, leaf number was not significantly affected. Soil salinity and drainage-water salinity both increased with increases in irrigation-water salinity. Salinity stress resulted in a yield-response factor (K-y) of 1.481, with a threshold value of 1.21 dS m(-1) and a decrease in yield slope of 9.622% per unit increase in soil salinity beyond the threshold value. Leek plants were found to be moderately sensitive to salinity. The findings of the present study suggest that if appropriate leaching and drainage systems are applied, slightly saline water can be used for irrigation with little or no soil damage and minimal decreases in plant yield, thus saving large amounts of water for the cultivation of more salt-sensitive crops as well as for industrial and domestic usage. (C) 2016 Elsevier B.V. All rights reserved.