Agriculture leads to taxonomic and functional homogenization of soil microbial communities globally. A continental survey of 1185 soil samples from croplands and adjacent natural ecosystems (forest, grassland, wetland) and a global meta-analysis of over 2400 samples across six continents show that land conversion to agriculture reduces soil microbial diversity and increases the geographic range of taxa in croplands. Croplands are enriched in Chloroflexi, Gemmatimonadota, Planctomycetota, Myxococota, and Latescibacterota, while functional genes involved in nitrogen fixation, phosphorus mineralization, and transportation are depleted. Although there is no significant difference in functional composition between natural ecosystems and agricultural land, agricultural conversion reduces functional diversity. The study highlights the importance of considering biotic homogenization as a significant consequence of agricultural conversion, which affects ecosystem services and biodiversity. The results suggest that agricultural conversion leads to taxonomic and functional homogenization of soil microbiomes, with implications for soil health and agricultural productivity. The study provides a global insight into the consequences of land-use change on soil microbial diversity and function.Agriculture leads to taxonomic and functional homogenization of soil microbial communities globally. A continental survey of 1185 soil samples from croplands and adjacent natural ecosystems (forest, grassland, wetland) and a global meta-analysis of over 2400 samples across six continents show that land conversion to agriculture reduces soil microbial diversity and increases the geographic range of taxa in croplands. Croplands are enriched in Chloroflexi, Gemmatimonadota, Planctomycetota, Myxococota, and Latescibacterota, while functional genes involved in nitrogen fixation, phosphorus mineralization, and transportation are depleted. Although there is no significant difference in functional composition between natural ecosystems and agricultural land, agricultural conversion reduces functional diversity. The study highlights the importance of considering biotic homogenization as a significant consequence of agricultural conversion, which affects ecosystem services and biodiversity. The results suggest that agricultural conversion leads to taxonomic and functional homogenization of soil microbiomes, with implications for soil health and agricultural productivity. The study provides a global insight into the consequences of land-use change on soil microbial diversity and function.