Fatimids (297-567 AH) were the Shi’a caliphs who, after a period of organizational secret activities by the Isma’ili Da’wa organization, made use of the capacities existing among Berber tribes in north Africa to establish a state, conquering Egypt and founding Cairo, and revealing their perspective in progressing and conquering the Islamic East, rivaling with Abbasid caliphate. This Shi’a minority could manage to dominate a vast region of Islamic lands with Sunni and Dhemmi inhabitants for more than two and a half century. In some eras, such as the first caliphate period in Egypt, they had a high popularity and authority as well. We know that the successes of Fatimid government in controlling and managing the country’s affairs were the result of their social approach and policies. One of the Fatimid’s social policies was their interaction with tribes and their use of tribal capacities of Maghrib and Egypt. The Kutama Berber tribe was the most important and the greatest supporter of Fatimids in periods of Da’wa and establishment of the government. The main question of this article is as follows: “What was the role of this tribe in establishing the government and ultimate result of the activity of this tribe in Egyptian government?” The finding of this study is that Kutama tribe in Da’wa period, especially since the presence of the Shi’a Abu Abdullah in Maghrib, was the main supporter of the Fatimid government. This role was continuous during the whole period of Maghrib and the early years of caliphate in Egypt until it was weakened under Abdul Aziz with the entrance of other tribes, especially Mushariqa, and it vanished after the entrance of Badr al-Jamali into Cairo, when Kutama tribe turned into an ordinary tribe.