Snow mold fungi are psychrophilic (cold-loving) or psychrotrophic (cold-tolerant) fungal pathogens of perennial grasses, winter cereals and trees. These fungi can grow and attack dormant plants at low temperatures under snow cover. In this mini-review, I describe the biodiversity, physiological and biochemical characteristics of snow mold fungi in various taxa in oomycetes, ascomycetes and basidiomycetes. Chilling or frost resistance are one of the important factors correlated with the geographical distribution of snow mold fungi. Snow mold fungi develop mycelia under snow cover. Therefore, they should produce extracellular enzymes active at low temperature for fungal infection.  Snow mold fungi, which are in basidiomycetes, also produce antifreeze proteins in extracellular spaces. The physiological significance of antifreeze proteins of snow mold fungi is that antifreeze proteins prevent freezing of the extracellular environment.