The genus Dioicomyces is reviewed on the basis of the examination of types, authentic material, or personal collections. Three new species from Spanish anthicids are described: D. denticulatus, D. ladoi, and D. leptalei spp. nov. Eleven taxa (including eight species, two forms, and one variety) are synonymized and included under D. anthici, which is considered a very variable species. With additions and changes, Dioicomyces currently includes 23 species. In this synopsis no taxa at infraspecific rank are recognised. For each accepted species synonyms are listed, mostly based on the study of type material. Types for each taxon are included and lectotypes designated when necessary. This monograph also includes descriptions, photographs and/or drawings for all species studied and a key for their determination.