This study investigates the global diversity and biogeography of soil fungi. Using 365 soil samples from natural ecosystems, the researchers determined the main drivers and biogeographic patterns of fungal diversity and community composition. Soil fungi were identified using pyrosequencing and compared against taxonomically and functionally annotated databases. Multiple regression models were used to analyze the roles of climatic, spatial, edaphic, and floristic parameters on fungal diversity and community composition. Structural equation models were used to determine the direct and indirect effects of climate on fungal diversity, soil chemistry, and vegetation. The study also examined whether fungal biogeographic patterns matched those of plants and animals. The results showed that distance from the equator and mean annual precipitation had the strongest effects on fungal richness. Diversity of most fungal groups peaked in tropical ecosystems, but ectomycorrhizal fungi and several fungal classes were most diverse in temperate or boreal ecosystems. Many fungal groups exhibited distinct preferences for specific edaphic conditions. Consistent with Rapoport's rule, the geographic range of fungal taxa increased toward the poles. Fungal endemicity was particularly strong in tropical regions, but multiple fungal taxa had cosmopolitan distributions. The conclusions indicate that climatic factors, followed by edaphic and spatial patterning, are the best predictors of soil fungal richness and community composition at the global scale. Fungal richness is causally unrelated to plant diversity, except for ectomycorrhizal root symbionts. Fungi follow similar biogeographic patterns as plants and animals, with some major taxonomic and functional groups deviating from overall patterns. Strong biogeographic links among distant continents reflect efficient long-distance dispersal compared with macro-organisms.This study investigates the global diversity and biogeography of soil fungi. Using 365 soil samples from natural ecosystems, the researchers determined the main drivers and biogeographic patterns of fungal diversity and community composition. Soil fungi were identified using pyrosequencing and compared against taxonomically and functionally annotated databases. Multiple regression models were used to analyze the roles of climatic, spatial, edaphic, and floristic parameters on fungal diversity and community composition. Structural equation models were used to determine the direct and indirect effects of climate on fungal diversity, soil chemistry, and vegetation. The study also examined whether fungal biogeographic patterns matched those of plants and animals. The results showed that distance from the equator and mean annual precipitation had the strongest effects on fungal richness. Diversity of most fungal groups peaked in tropical ecosystems, but ectomycorrhizal fungi and several fungal classes were most diverse in temperate or boreal ecosystems. Many fungal groups exhibited distinct preferences for specific edaphic conditions. Consistent with Rapoport's rule, the geographic range of fungal taxa increased toward the poles. Fungal endemicity was particularly strong in tropical regions, but multiple fungal taxa had cosmopolitan distributions. The conclusions indicate that climatic factors, followed by edaphic and spatial patterning, are the best predictors of soil fungal richness and community composition at the global scale. Fungal richness is causally unrelated to plant diversity, except for ectomycorrhizal root symbionts. Fungi follow similar biogeographic patterns as plants and animals, with some major taxonomic and functional groups deviating from overall patterns. Strong biogeographic links among distant continents reflect efficient long-distance dispersal compared with macro-organisms.