Phosphorus is the second most necessary macro-element for plant growth and development, just after nitrogen. Fixing of phosphorus in soils mostly depends on the pH value of soil, soil moisture, temperature and present soil minerals. Phosphorous solubilizing bacteria (PSB) have different mechanisms by which plant unavailable phosphorous forms can be transformed into available forms to plants, thus affecting phosphorus reserves in the soil. The aim of this study was to determine the effect of microbiological preparation and phosphorus fertilization on the yield, quality and germination of soybean and corn seeds groen on acidic soils. Three locations with soils of similar pH values, different content of humus and concentration of available phosphorus were selected. The researches included a two-year field experiment and analysis of plant material and soil. As a microbiological preparation, a commercial preparation named Terra Condi, producer EmTehnologija d.o.o. from Valpovo, to which bacteria Pseudomonas putida (ATCC 12633), Pseudomonas rhizosphaere (DSM 16299) and Pseudomonas fluorescens (ATCC 13525) were added as phosphorous solubilizing bacteria. It was found that the Pseudomonas strains adapted to the soil of all sites. The control treatment with microbiological preparation recorded higher average yields of soybean and corn at all sites compared to the control treatment without the use of the microbiological preparation. The average amounts of microbially fixed phosphorus ranged from 23.34 to 88.88 kg ha-1. Also, there ware found very significant positive correlation (r = 0.89) between the concentration of available phosphor (AL-method) and the amount of microbially-fixed phosphorus, as well as between the humus content in soil and the increase of microbially-fixed phosphorus (r = 0,81). The average values of soybean germination ranged from 91.9 to 93.4%, and corn from 92.6 to 93.8%. Additional and longer-lasting researches under field conditions are needed to better determine the effects of the microbiological preparation.