In Apulia, and especially in Salento, in Southern Italy, irrigation water used in agriculture is underground water coming from water-bearing stratum of Karst nature. Irrigated agriculture of Mediterranean areas depends on adequate water supply of usable quality. Water quality concerns in tobacco cropping systems have often been neglected because good quality water supplies have been readily available. Tobacco growing in Mediterranean areas is going to suffer severe restrictions, already evident for others cash crops (vegetables and fruits). At present, there are very few studies on the effect of salinity on field-grown tobacco. Salinity problems are evident mainly during summer because of the high evaporative demand due to high temperature and high plant water absorption during this period. As a consequence, an accumulation of salts in the root zone takes place and this accumulation affects both chemical and physical soil properties. Sodium chloride (NaCl) salinity has a potential negative effects on tobacco because of the effect of excessive chloride on qualitative characteristics and leaf texture. The collected data agreed with the results of a previous research that underlined the variability of chemical and physical water parameters in Salento, depending both on climatic events (rainfall and temperature) and on the intensity and frequency of the extracting of underground water (Cotecchia, 1977; Lombardi, 2003). As for irrigation waters, there is currently no problem of salinity in both Italian sites. The ECw was higher than 2 dS m-1 only in few cases, with peaks of 4 and 5 dS m-1 in few cases in Apulia region. The objectives of this research are to individuate the morphological and physiological responses of plants in their growing stages to salt stress conditions induced by irrigation water, to individuate the genotypes of tobacco which demonstrate better tolerance to salt stress effects. To investigate the four genotypes of tobacco,with a different genetic background, response to salt stress an in pot experiment was conducted in order to study the effects of NaCl on plants. Plants were irrigated with saline water at four different NaCl concentrations (0%, 0.25%, 0.50%). The response of genotypes of tobacco to increasing salt stress was investigated in the whole plant and during the crop cycle (growth, physiology and yield). The effects of the 3 different levels of salt stress induced by irrigation with saline water (0%; 0.25%; 0.50% NaCl) on the 4 different genotypes of tobacco (Coker 48; NC 2326; Bel 4-30; Mc Nair 944) were tested, in accordance with the arranged experimental design. The statistical analysis of the experimental data was carried out on the different genotypes of tobacco and on the different salinity levels. The analysis of the plant growth under salt stress was carried out; all the determinations included: dry matter(dm) storage, leaf area development and plant's biometric parameters. Tobacco genotypes grown in pots subjected to four growing levels of NaCl, given by localized irrigation, were influenced by the saline treatment level. Biometric parameters such as number of leaves, leaf dimensions, plant total height and internode length showed. In the two growing seasons the yield of green leaves of tobacco, belonging to the tested lines which were used in these two years and subjected to the three different salt-stress (NaCl 0%, 0.25%, 0.50%), showed significant differences (P = 0.05) between years and significant differences between treatments, there was also a significant interaction (P = 0.05) between treatment and year. In these two years treatment NaCl 0.50% differed from control level and NaCl 0,25%, since it showed a greater yield of green leaves, according to Duncan's test.