Abstract: The present work aimed at monitoring the abundance and diversity of indigenous P. fluorescens organisms in three different ecosystems. The number of culturable P. fluorescens organisms was counted on the King’s medium B and identified by the use of the Analytical Profile Index (API 20 NE; bio Merieux), data are reported as CFU g-1. Quantitative results have confirmed that P. fluorescens are successful root colonizers occupying different ecological niches, with the dominance of Biovar I (80%). P. fluorescens distribution were correlated significantly (p<0.05) with the majority of soil properties. Pearson’s correlation coefficients of the relationship between P. fluorescens abundance and soil physicochemical properties indicated a significant (p<0.05) positive correlation. However, P. fluorescens abundance displayed a negative linear relationship with pH (r = 0.62) and clay (r = 0.51). No significant (p>0.05) relationships for the organic matter (r = 0.13, p = 0.48) and soil depth (r = 0.099, p = 0.62). The present findings suggested that the abundance of P. fluorescens may be strongly influenced by some abiotic and biotic factors.