Entomopathogenic fungi offer an eco-friendly solution for managing insect pest problems in a wide range of crops. Their insecticidal properties not only help control pests but also contribute essential nutrients to the soil and plants, thereby enhancing soil fertility. This nutrient-recycling ability underscores their potential role in sustainable soil health management. Both entomopathogenic and endophytic fungi produce a variety of enzymes, including cellulase, ligninase, chitinase, pectinase, amylase, and lipase, which facilitate the breakdown of complex organic matter and enhance nutrient availability for other organisms. Additionally, these fungi participate in the mineralization and solubilization of essential macro- and micronutrients in the soil. Numerous studies have reported their capacity to solubilize phosphorus and zinc through the production of organic acids. Moreover, the transfer of nutrients such as nitrogen, carbon, and iron from insect cadavers to plants and soil has also been documented, highlighting their role as nutrient mobilizers. The enrichment of soil with these nutrients supports a more diverse microbial community, enhances soil biodiversity, and improves overall soil physiology and biological activity. The presence of entomopathogenic and endophytic fungi in the soil thus indirectly promotes soil fertility and contributes to better soil health. This chapter discusses the role of these fungi in nutrient mobilization and their enzymatic degradation potential in promoting soil fertility. It also explores the endophytic behavior of certain entomopathogenic fungi and their involvement in nutrient translocation between soil and plants.