This study investigated the effect of plants inoculation with Azospirillum spp. and Pseudomonas stutzeri in soils freshly contaminated with PAH's on enzymatic activities. During the 30-days experiment a relatively higher dehydrogenase, acid and alcaline phosphatases activities were detected in chernozem and rendzina after grown of maize and meadow feascue inoculated with Azospirillum spp. and Pseudomonas stutzeri. Statistically important decrease of enzymatic activities in soil after grown of plants non-inoculated and inoculated were confirmed after pollution of soils with diesel fuel at the dose of 1%.