alinity is an important environmental stress which negatively affects the yield of different agricultural crops in many growing areas of the word. In this study three experiments were conducted to evaluate the response of different safflower genotypes to salinity and also to investigate the role of potassium and calcium in the salt tolerance of safflower plants. In the first experiment the effects of salinity at germination stage was studied in laboratory. The second and third experiments were carried out in green house to study the effects of salinity on safflower plants at vegetative stage using hydroponic nutrient solution. Thirteen safflower genotypes were evaluated in the first and second experiments at two levels (0 and 100 mM) of NaCl. In third experiment the response of a sensitive safflower genotype to salt stress was studied with consideration of two levels of salinity (0 and 100 mM of NaCl) and four nutrient treatments (Johnson solution, Johnson solution + 10 mM potassium, Johnson solution + 5 mM calcium, Johnso solution + 10 mM potassium and 5 mM calcium) as experimental factors. The germination rate and percentage and the root and shoot length of germinated seeds were reduced under saline treatments. The effects of the interaction between salinity and genotype on germination factors were not significant. Plant height, number of leaves per plant, leaf area index, and shoot and root dry matter were decreased at saline treatments. The reductions in shoot dry matter in saline compared to non saline treatment were about 32 percent for the most and about 60 percent for the least tolerant genotype. The concentration and the content of potassium, calcium, and magnesium in the shoots and roots were decreased but those of sodium were increased at salinity. The reduction in shoot dry mater at salinity was less in the treatment in which the concentration of calcium was increased. Increasing the concentration of potassium and calcium together in solution led to a bigger reduction in shoot dry matter at salinity. The results of this experiment show that the negative effects of salinity can be mitigated by increasing the concentration of calcium in nutrient solution.