The characterization of PGPR (plant growth promoting rhizobacteria) bacteria associated to Agrostis cap-illaris, and evaluation of plant growth promotion mechanisms, as well as correlation of them with thepotential effects on the growth of the plants in unfavorable conditions, in order to improve the efficiencyof phytoremediation of contaminated soils were investigated. The results indicate that in the presenceof bacterial inoculation the growth of plants on heavy metal contaminated soil was higher compared touninoculated plants, which confirms the PGPR characteristics of selected isolates. To demonstrate theeffects in plant growth the different variants of plants inoculation were applied. The inoculation of rapeand fescue grass with PGPR bacteria, directly during germination as well after two weeks of growth, werethe most efficient methods for protecting seeds from growth inhibition on heavy metal contaminatedsoil. The bacteria associated with plant rhizosphere naturally occurring in contaminated areas due to thebiochemical activity stimulate plant growth and thus improve the soil phytoremediation process.