Folk classification is largely based on a long history of observing and harvesting living organisms. Although epistemologically undervalued by Western modern science, the study of ethnomycological classifications by indigenous populations has recently received increased attention. The classification criteria for fungi of several Brazilian indigenous groups, including the Caiabi, Txicão, Txucarramãe, Tupi-Guarani, and Yanomami, are similar to those used in classical, morphology-based taxonomy. The Yanomami, due to their long history of mycophilic behavior, show impressive knowledge of fungal classification similar in some cases to the recently proposed phylogenetic classification. This suggests that indigenous traditional knowledge may be helpful in the development of fungal systematics, reinforcing the epistemological validity of these distinct forms of knowledge of the natural world.