BACKGROUND: Salinity is one of the main environmental stresses deteriorating qualities as well as yields of food crops. This study was conducted to identify the effects of salt stress on dry matter ratio, glucose content, and mineral content and composition in potatoes (Solanum tuberosum L.). METHODS AND RESULTS: Four potato varieties were grown in plastic pots (diameter 20 cm and height 25 cm) with three salinity levels (EC: 1.0, 4.0, and 8.0 dS/m) in a glasshouse. Dry matter ratio, specific gravity, starch, and glucose content in tubers harvested at 90 days after sowing were analyzed. Also, mineral contents (T-N, T-C, P 2 O 5 , K + , Ca 2+ , Mg 2+ , Na +) in stem, leaf, and tuber were investigated and statistically analyzed for analysis of variance (ANOVA). Dry matter ratio, specific gravity, and starch content in tubers were reduced in all varieties as the salt concentration increased. Glucose content tended to decrease according to the salt concentration. In ANOVA analysis of mineral contents, there were significant differences in K + and Mg 2+ of leaf and stem, in Na + of leaf and tuber, and also in Ca 2+ of leaf by the interactions of variety and salinity. In the case of K + /Na + and Ca 2+ /Na + , the stem was more sensitively influenced by the salt treatment than the leaf or the tuber. The K + /Na + and Ca 2+ /Na + decreased in leaf, stem, and tuber of four varieties, as the salt concentration became higher. The decreasing level varied according to the varieties. 'Kroda' and 'Duback' maintained relatively higher K + /Na + and Ca 2+ /Na + than 'Atlantic' or 'Goun' under the salt stress conditions. CONCLUSION: The composition and accumulation of minerals in potato plant as well as dry matter ratio, starch, and glucose contents were significantly influenced by salt stress. The respond patterns were different depending on the varieties and it was related to the salt tolerance among varieties.