Herein, we described three types of fossil fungi associated with permineralized legume wood from Upper Miocene deposits in the Río de Agua Verde locality (Chiquimil Formation, Catamarca Province, Argentina). These are represented by diverse fungal remains, including septate hyphae bearing unicellular and multicellular conidia, distributed inside the vessel elements. Vegetative and asexual reproductive structures preserved were compared to extant mitosporic fungi and related to three different genera. The fossils are particularly similar to extant Gilmaniella Barron, Brachysporium Saccardo, and Ramichloridium Stahel ex de Hoog, but display some differences that preclude unequivocal assignment. Due to the absence of host reactions signs in the infected wood, we suggest that the fungi were probably saprotroph and invaded the fossil wood after its death.