The family Fomitopsidaceae is a group of fungi within the order Polyporales and class Agaricomycetes, primarily composed of wood-decaying species that play a key role in forest ecosystems as decomposers. Members of this family typically form tough, woody, bracket-like or resupinate fruiting bodies on dead or living trees, causing brown rot, which breaks down cellulose and hemicellulose while leaving lignin largely intact. Fomitopsidaceae species are mostly saprotrophic or parasitic, commonly found on conifers and hardwoods, and include genera such as Fomitopsis, Antrodia, and Daedalea. They are characterized by a poroid hymenophore, slow-growing perennial basidiocarps, and a filamentous hyphal system with clamp connections in many species. These fungi are ecologically important for nutrient cycling and have been studied for biotechnological applications, including biofuel production and medicinal compounds.