The objective of this work was to do a comparative study of Pseudomonas and Bacillus isolates for their plant growth-promoting (PGP) potential, monitoring the impact of selected isolates on the yield of English ryegrass (Lolium perenne). Isolation, physiological and biochemical characterization, in vitro assay of enzymatic and plant-growth promoting activities of isolates were done. Pseudomonas isolates have been shown to have the ability to use different sources of carbon, to live in the condition of low pH as well as temperature and to produce siderophore. On the other hand, Bacillus isolates have the ability to solubilize phosphate, to produce a greater amount of indol-3-acetic acid (IAA) than Pseudomonas isolates and have an inhibitory effect on the growth of phytopathogenic fungi. In other investigated traits, isolates were similar. The use of Pseudomonas sp. P12 and Bacillus sp. B1 isolates had a positive effect on the plant mass and total yield, which indicate that the use of these isolates can result in a better yield of forage crops.