The article focuses on the analysis of the ideology that defines the military-political doctrine of the Islamic Resistance Movement (HAMAS), which for more than thirty years, along with Fatah, is the most influential political force in the territories controlled by the Palestinian National Authority. The study shows that the ideology of Hamas, developed by Sheikh Ahmed Yassin, is based on two components: the classical Salafi concepts of the Muslim Brotherhood society founders and the national-religious doctrine and political practice of Sheikh Izz al-Din al-Kassam who was very popular among the marginal unity of the Palestinian society in the 1930s. The main source for studying the ideology of HAMAS is the Charter of the Islamic Resistance Movement. The anti-Semitic, anti-Israeli and frankly jihadist provisions embodied in the document by HAMAS militants in practice have had an extremely unfavorable effect on the already strained Palestinian-Israeli relations. The process of Oslo was curtailed, and the arrival of HAMAS to power actually blocked the activities of the “quartet” of international mediators and other efforts to resolve the Palestinian-Israeli conflict. The strengthening of HAMAS also split the Palestinian society. The program document analyzed in the article demonstrates that the new political leadership of the organization understands that in the current deadlock situation it requires more flexible approaches to solve the important foreign policy issues. This, in particular, is evidenced by the recent cardinal reform of the Charter of the Islamic Resistance Movement.