The families living in Yazd, historically originate from different groups of people; namely Zoroastrians, Sadats (the descendents of the holy prophet Mohammad, P.B.U .H.), kinsfloks, doctors, tribal chiefs, and the emigrants coming from other cities. They generally form the composition of Yazd population, living indistinctively and peacefully. These groups of people have been intermixing for years and have given rise to new families having new identities. At the present time, they can be divided into nine groups, many of whom have initiated public endowments, public facilities, and industrial] establishments. To study issues such as public facilities and services, industrial establishments, and public endowments in Yazd, it is therefore needed to take into account the family background and their genealogy first.