As a result of the Islamic conquests during the first century of Islam, the North Africa and al-Andalus have been conquered alongside with the other regions. During these conquests, the great amount of Berberi elements were also in the Muslim army in addition to the soldiers and commanders of Arabic origin. In this article, it has been studied the origin, identity and pre-Islamic history of the Berbers in brief. Apart from this, it has been also examined the political and military relations between the Arabs and the Berbers, Islamization of the Berbers and their roles in the conquests of the North Africa and al-Andalus in the light of primary sources alongside with the contemporary researchs.