This research was conducted in 2013 to investigate changes in some physiological traits of spring safflower cultivars (C1; Faraman, C2; Goldasht; C3; Sina and C4; Soffeh) under different irrigation treatments (I1, I2, I3, I4 for irrigation after 70, 100, 130 and 160 mm evaporation from class A pan, respectively). The experiment was arranged as split plot based on randomized complete block design in three replicates. Relative water content (RWC), membrane stability index (MSI) and total chlorophyll decreased, but leaf temperature, proline content and soluble carbohydrate content of all safflower cultivars increased with decreasing water availability. The highest increment in proline content and a sharp decline in total chlorophyll due to water deficit was recorded for Goldasht, indicating that this cultivar is less tolerant to drought stress. In contrast, Sina had the lowest proline content and the highest soluble carbohydrate content under all irrigation treatments.International Journal of Life Sciences 10 (1) : 2016; 58-64