SummaryThe response of potato cultivars to water salinity was studied under field conditions in sandy loessial soil in the arid desert of Southern Israel. The potatoes were drip‐irrigated with water of three different salinities: water commonly used for irrigation (1.0–1.4 dS m‐1); saline water from a local well (6.1–6.9 dS m‐1); and a mixture of the two (3.84.3 dS m‐1). Salinity retarded plant emergence, enhanced haulm senescence and reduced growth of both haulms and tubers. Increasing the salinity progressively reduced tuber yields. Application of the saline water well after plant establishment (Expt A) decreased tuber yields by 615% and 22–31% in the intermediate and the high salinities, respectively. When irrigation with saline water was started soon after planting (Expt B), tuber yields were decreased by 0–17% and 21–79% in the intermediate and the high salinities, respectively. When the tubers emerged in salinised soil, tuber yields were decreased by 21–54% and 42–59% in the intermediate and the high salinities, respectively. A differential response of various cultivars to salinity was observed. None of the potato cultivars or clones exhibited exceptional tolerance to severe salinity. The earlier maturing cvs Atica and Désirée were the least susceptible to the moderate salinity imposed throughout the entire growing season; however, no association was noted between maturation time and t