The Umayyad Empire (661-747 CE), the first dynasty of Islam, reigned nearly ninety years after the so-called Rashidun era, was collapsed by the. Abbasid Revolution (AR). After 750, the. Abbasids became the new rulers of the Islamic empire through the culmination of an orchestrated secret campaign lasting more than thirty years and based on popular unfavourable views of the Umayyads. Although extensive research has been carried out on the AR, there have been no studies which try to understand the AR with reference to modern economic and Revolution theories by focusing upon the economic dissatisfaction of the Khurasani mawali who supported the Revolution. The aim of this paper is to discuss the theory that economic disorder in Khurasan was an important reason for the AR, by focusing on the taxation system in Islam and its abuse in the later Umayyad period (685-747) as well as by evaluating modern Islamic historiography in this perspective.