Wheat is the most important cereal crop in the world as well as in Iran. The studies related to the effects of global climate change on wheat production usually assess the impact of changes in air CO 2 concentration and temperature on growth and yield. On the other hand, nitrogen is the most crucial plant nutrient for crop production. The proper management and improving the utilization efficiency of nitrogen fertilizers is very important. Two greenhouse experiments were, therefore, conducted to assess combined effects of CO 2 concentration, temperature and nitrogen supply on the growth, dry matter partitioning and some physiological traits of Bahar bread wheat cultivar. In the first experiment effects of four nitrogen levels (0, 50, 100 and 150 mg kg -1 from ammonium nitrate source, N=34.4%) at two environments, one with an ambient temperature of 25 ± 3°C and the other with elevated temperature of 35 ± 3°C were tested on the latter wheat genotype in a completely randomized design with three replications. The results were suggestive of decreases in the leaf stomatal conductance (44.5%), plant leaf area (36%), chlorophyll a concentration (12.5%), chlorophyll b concentration (14.2%), carotenoid concentration (14.7%), leaf protein concentration (9.7%), root dry weight (26.1%), shoot dry weight (27.2%), root nitrogen concentration (26.3%) and nitrogen use efficiency of shoot (18%) and increases in shoot nitrogen concentration (43.5%) and nitrogen use efficiency of root (18.6%) with increasing temperature. Elevated temperature led to 7.6 cm 2 (62%), 5.9 cm 2 (53%), 4 cm 2 (26%) and 0.5 cm 2 (4%) decreases for leaf area/plant, respectively, and 0.184 (41%), 0.019 (3%), 0.027 (5%) and 0.068 (13%) mg g -1 FW decreases for carotenoids concentration at 0, 50, 100, and 150 mg kg -1 levels of nitrogen fertilizers, respectively. Exposure to ambient temperature in the presence of 50, 100 and 150 mg kg -1 of N fertilizer led to 21, 12 and 38 percent increases in plant root weight compared to non-fertilized control (2.18 g plant -1 ) respectively, and exposure to an elevated temperature at the presence of the mentioned levels of fertilizer led to 16, 35 and 6 percent increases compared to control (1.16 g plant -1 ), respectively. Increased temperature decreased shoot dry weight by 1.16 g or 50%, 0.47 g or 21%, 0.45 g or 16% and 0.81 or 26%, respectively, in the presence of 0, 50, 100 and 150 mg kg -1 of nitrogen fertilizer. Under these experimental conditions, the maximum shoot dry matter belonged to 150 mg kg -1 of nitrogen fertilizer at ambient temperature and 100 mg kg -1 of soil nitrogen fertilizer at an elevated temperature. Shoot-NUE increased under effect of high temperature in the control treatment by 6.08 unit or 67% but it decreased by 2.64 unit or 28%, 4.95 unit or 41% and 6.0 unit or 53% in the presence of 50, 100 and 150 mg kg -1 of soil nitrogen fertilizer, respectively. The second experiment was conducted using four nitrogen levels (0, 50, 100 and 150 mg kg -1 ) in a completely randomized design with three replications in each of the four different environments, i.e. two air carbon dioxide concentrations (ambient CO 2 of 390 ± 50 µmol mol -1 and enriched CO 2 of 700 ± 50 µmol mol -1 ) and two air temperatures (ambient temperature of 25 ± 3°C and elevated temperature of 35 ± 3°C). The results showed that the mean ratio of shoot/total biomass (S/TB) decreased by 7% , averaged over the three levels of N fertilizer, under effects of CO 2 enrichment, but it increased by 30% when the wheat plants were deprived of any N fertilizer, i.e. control treatment. In conclusion, these results suggest that the rate of nitrogen fertilizer for a better performance of Bahar bread wheat cultivar depended on air carbon dioxide concentration and temperature. These findings are potent to benefit breeding programs and the management strategies for mitigating the influence of climate change on wheat production. Keywords: Assimilate partitioning, air carbon dioxide, climate change, high temperature, fertilizer N use efficiency, wheat