A field experiment was carried out during 2002 at Al-Husainea - Deer Al- Zour to study the effect of PSB (Pseudomonas) or PSB combined with 50%, 25%, 100 % of the recommended phosphorus (P2O5) mineral fertilizer without inoculation on cotton productivity, phosphate uptake . Significant differences in available phosphate were noticed in comparison with the control. These microorganisms were effective in solubilizing of fixing phosphate in soil and fixing phosphate, added to the soil as superphosphate. Significant increasing in cotton yield of inoculating treatments was noticed in comparison with the control.