Plant growth-promoting rhizobacteria possessing ACC deaminase activity reduces the level of stress ethylene, conferring resistance and improving plant growth under different stress conditions. The present study aims at evaluating Pseudomonas fluorescens strains for their potential to produce ACC deaminase and quantifying their effects on seed germination and seedling growth of wheat under salinity stress. Bacteria were first evaluated for their ability to utilize ACC, an immediate precursor of stress ethylene, using DF minimal medium containing 3 mM ACC and it was revealed that they were all able to use ACC as sole nitrogen source under in vitro conditions. Thereafter, the influence of bacterial strains on seed germination and seedling growth of wheat varieties was evaluated under NaCl induced salt stress after seven days. The experimental design was completely randomized in 3×5×5 factorial scheme with three replications. Factors consisted of salinity (0, 3 and 6 dS/m), P. fluorescens bacteria (strains PGU2-79, WBO-3, WKZ1-93 and WB1-7 and sterile water as control), and wheat variety (Chamran, Kooh-Dasht, Dehdasht, Karim and Jam). Twenty wheat seeds were transferred to plates after being soaked for an hour in bacterial suspensions at concentration of 10 8 CFU/ml. Each plate contained a filter paper which was moistened with 10 ml of NaCl solution in different concentrations. Plates were incubated in a growth chamber with maximum and minimum temperatures maintained at 20°C and 15 °C, respectively, with 12 h day-night photoperiod and relative humidity of 80%. Results revealed that P. fluorescens strains had positive impacts on different growth parameters of wheat varieties including germination percentage and rate, seed vigor, length and dry weight of coleoptile and radicle and salinity tolerance index of plants under salinity stress as compared to control. This study reveals the efficacy of plant growth promoting P. fluorescens strains containing ACC deaminase for improving salt tolerance and consequently stimulating the growth of wheat seedlings under salinity stress.