Technical Abstract: This chapter provides an in-depth review of what is and is not known about the soil ecology of the entomopathogenic Ascomycetes, particularly the fungi Beauveria bassiana and Metarhizium anisopliae. The efficacy of entomopathogenic fungi in soil is subject to a matrix of interlocking abiotic and biotic factors. This review examines what is known about how certain soil factors – temperature, texture, moisture content, agricultural inputs, soil microbes, the rhizosphere, fungal genotypic variation, and formulation – affect not only the persistence and but also the infectivity of these fungi. In critically reviewing the literature the author remarks that there are relatively few thorough studies by which the scientific community has gained a better understanding of the soil ecology of these fungi. While there are numerous papers on the subject many have critical flaws that limit their usefulness. And, if a generalization can be made, it is that one simply cannot generalize. Detailed and comprehensive interdisciplinary research is badly needed, if we are to utilize EPF against soil pest insects with consistent efficacy. New tools have evolved in recent years in the study of plant pathogenic fungi and their biocontrol. Many of these tools are relevant to studying EPF and, indeed, must be used to understand more clearly what is going on with “our” EPF in the soil environment.