Endemic populations of Abies religiosa (fir, oyamel) have great economic, ecological and social importance; in addition, they form different interactions with edaphic microorganisms, mainly with ectomycorrhizal fungi. Currently, isolated populations (i. e. fir) are threatened by deforestation, agricultural expansion and global warming; therefore, it is urgent to understand the ecological and evolutionary interactions with ectomycorrhizal fungi. The objective of the present research was to analyze the use of molecular ecology, taxonomy and biology of ectomycorrhizal fungi to understand the role that these fungi play in A. religiosa trees in Mexico. Areas of research are presented as well as the main information gaps in the morphological/molecular characterization, taxonomy and evolution of the ectomycorrhizal symbiosis in A. religiosa. For the above, we collected information of 108 taxa of potentially ectomycorrhizal fungi obtained from different fir populations. The taxa with high potential to inoculate A. religiosa are Sebacina dimitica, Clavulina cf. cinerea, Membranomyces sp., Thelephoraceae, Russula spp., Ramaria spp., Lactarius spp. e Inocybe spp. Finally, we discuss issues that remain unresolved to determine their potential for use, management and conservation of A. religiosa in temperate areas of Mexico. This problem can be solved by combining molecular tools with the morphological and histological description of ectomycorrhizal morphotypes. In addition, methodologies are required to standardize results to come to more robust conclusions about mycorrhizal interactions.