As a matter of fact, the phenomenon of takfeer is not a new occurrence in the religious history, but, it has been associated with and accompanied by it. Undoubtedly. There are some people who believe in the religious precepts and rituals, so they are considered believers. And, on the contrary side, those who do not believe in them, they would be categorized as unbelievers. Hence this affair is not new by itself, and we cannot deny it as a doctrinal actual state. But in fact, the problem lies in another place, which is deeming it (takfeer) easy within the believing or doctrinal framework, to the extent that some Islamic movements have been blamed for their failure in labelling the rulers or others of disbelief. Besides, it lies too, in the belief that killing is the only means to deal with every one who has been categorized in the circle of disbelief (kufr), with the entrance of many historical, political, and sectarian factors.At any rate, these factors will increase the subject with confusion and dubiosity, particularly, when they have led to the production of takfeery heritage which has become very hard to analyze and criticize, except by those who hold or possess genuine, far-sighted mind and thought, and those having objective and critical reason, who endeavour to pass over this heritage, and directly return to the basic major sources of religion. That is to say, they should refer to the Holy Glorious Qur’an and the Prophetic Sunnah, while attempting to judge this heritage in accordance with these major sources. None the less, takfeer (labelling some people of disbelief), which is done by some personalities to some other sects is mostly or wholly considered an affair affected by several factors. Of course, they need our thoughtful halt, careful study, and examination to find out and show clearly the nature of their effect, and how they take part in producing that phenomenon of takfeer among the religious sects. For this reason, we should investigate and think seriously of these factors, and act earnestly to find out the real proper solution to the problem.