This study was conducted in two separate experiments under geenhouse conditions at Isfahan University of Technology, Iran in 2013. In the first experiment,20 wheat cultivars were evaluated under two concentrations of carbon dioxide (380 and 700 µM) and two concentrations ofnitrogen(75 and 150 g/L nitrogen in nutrient solution). The results showed different responses of the tested wheat cultivars to elevated CO 2 were positive in terms of dry matter accumulation, but to different extents.The positive effect of elevated CO 2 level was low (less than 40% increase in dry matter accumulation) in Pishtaz, Kavir, Karaj, Ghods, Chamran, Tajan, Alamut, Khoshki11, Sharyar, Karun, Sorkhtokhm, Omid, Marvdasht medium (between 40 and 80%) in Bahar, Shiraz, Shole, Sepahan, Gasparud and high (more than 80%) in Sistan and Navidcultivars. There were considerable differences among wheat cultivars in response to change in nitrogen concentration in nutrient solution. The extent of increase in shoot dry weight due to an increase in nitrogen level was less than 60% inChamran,Tajan, Khoshki11, Sharyar, Karun, Sorkhtokhm, Omid, Marvdasht,between 60 and 120% in Bahar, Pishtaz, Kvir, Sepahan, Karaj, Ghods, Gasparud, Alamutand more than 120% in Sistann, Navid, Shiraz, Shole cultivars.In the second experiment, four wheat cultivars, chosen from the first experiment, werestudied under two levels of carbon dioxide (380 and 700 µM), two concentrations ofnitrogen (75 and 150 g/kg soil) and two levels of salinity (0 and 150 mMNaCl of irrigation water). The results showed that with an increase in nitrogen level, the concentration and the content of nitrogen in shoot and roots, shoot/root nitrogen ratio, the concentration of chlorophyll a, chlorophyll and total chlorophyll in leaves, the concentration of carotenoids, plant height, root volume, shoot and root dry weight, planttotaldry weight and shoot/root dry weight were increased but the concentration of sodium in shoot and roots, nitrogen use efficiency in shoot and roots, shoot/root nitrogen ratio, the activities of catalase, ascorbate peroxidase and superoxide dismutase and shoot/root dry weight were decreased. With an increase in air CO 2 level, the concentration of potassium in shoot and roots, K + /Na + ratio in shoot and roots, the concentration of nitrogen in roots, nitrogen use efficiency in shoot, the concentration of chlorophyll a, chlorophyll and total chlorophyll in leaves, the concentration of carotenoids, plant height, root volume, shoot and root dry weight and planttotaldry weight were increased but the concentration of sodium in shoot and roots, the concentration and the content of nitrogen in shoot, nitrogen use efficiency in root, shoot/root nitrogen ratio, the activities of catalase, ascorbate peroxidase and superoxide dismutase, the concentration of proline and soluble carbohydrates and shoot/root dry weight were decreased. Salinity increased the concentration of sodium in shoot and roots, nitrogen use efficiency in shoot and roots, the activities of catalase, ascorbate peroxidase and superoxide dismutase and the concentration of proline and soluble carbohydrates but decreased the concentration of potassium in shoot and roots, K + /Na + ratio in shoot and roots, the concentration and the content of nitrogen in shoot and roots, shoot/root nitrogen ratio, the concentration of chlorophyll a, chlorophyll b and total chlorophyll in leaves, the concentration of carotenoids, plant height, root volume, shoot and root dry weight and planttotaldry weight. The results of this experiment showed that the increase in air CO2 concentration affected positively the gowth of the wheat cultivars and the extent of reaction depends on both salinity and nitrogen. Keywords: Climate change, Elevated CO2, Wheat cultivars, Salinity, Nitrogen, Ammonium nitrate.