Truffles are edible fungi belonging to the phylum Ascomycota. These valuable fungi can be divided into two categories: desert and forest truffles. They are obligatory mycorrhiza forming with some trees, shrubs, annual and perennial plants. These fungi belong to 38 genera of six families of the order Pezizales, class Pezizomycetes. The forest truffles are classified in the Tuberaceae family and the desert truffles in the other families. The existence of Tuber aestivum from the family Tuberaceae, Terfezia claveryi, Terfezia boudieri, Tirmania pinoyi, and Tirmania nivea from the family Pezizaceae, Picoa juniperi, Picoa lefebvrei, Geopora cooperi and Geopora cooperi, from the family Pyronemataceae, has been morphologically and molecularly proven by researches in Iran. The morphological characteristics, symbiotic plants, and distribution areas of these fungi are described here.