The chapter discusses the role of soil microorganisms in mediating phosphorus (P) availability to plants. Microorganisms play a crucial role in the soil P cycle, enhancing plant P nutrition and addressing P deficiency, which is common in weathered and tropical soils. The text reviews historical and recent research on microbial-mediated P mobilization, including mechanisms such as increased root growth, alteration of sorption equilibria, and induction of metabolic processes. It highlights the importance of microbial biomass in P cycling and turnover, and the impact of these processes on rhizosphere dynamics. The chapter also explores the mineralization of organic P and the solubilization of inorganic P by microorganisms, emphasizing the need for better understanding of microbial interactions and soil properties. Finally, it discusses the potential of using specific microbial inoculants to enhance P availability and the ecological considerations for future research and sustainable agricultural practices.The chapter discusses the role of soil microorganisms in mediating phosphorus (P) availability to plants. Microorganisms play a crucial role in the soil P cycle, enhancing plant P nutrition and addressing P deficiency, which is common in weathered and tropical soils. The text reviews historical and recent research on microbial-mediated P mobilization, including mechanisms such as increased root growth, alteration of sorption equilibria, and induction of metabolic processes. It highlights the importance of microbial biomass in P cycling and turnover, and the impact of these processes on rhizosphere dynamics. The chapter also explores the mineralization of organic P and the solubilization of inorganic P by microorganisms, emphasizing the need for better understanding of microbial interactions and soil properties. Finally, it discusses the potential of using specific microbial inoculants to enhance P availability and the ecological considerations for future research and sustainable agricultural practices.