The fossil record contains abundant evidence of the hyperdiverse kingdom Fungi. Macrofungi (Ascomycota, Basidiomycota) enter this record in the Paleozoic, some 360–540 myr ago. Common modes of preservation of macrofungi include impression, compression, petrifaction, and permineralization; delicate mushrooms may also occur as amber inclusions. Fossils have contributed greatly to our understanding of the roles fungi played in past ecosystems, including the various interactions they formed with other organisms. Yet, there are still major gaps in knowledge that are to be filled, especially with regard to the significance of fungal fossils as proxy indicators of paleoecological conditions and patterns.