Understanding the political-administrative structure that came out of the steppes of Mongolia in the thirteenth century and ruled over half the civilized world of its time has always occupied the minds of historians. From the beginning, the Mongols put their plans on the establishment of the government and its continuation, and for this purpose they created their own administrative system, albeit adapted from the government experiences of other more civilized nations. One of the practical systems used by the Mongols to maintain and expand their control over the conquered lands was the Tamma, which can be found in the early Mongol period, in Iran, Russia, and in the Golden Herd. This paper attempts to study the nature and function of the Tamma in Iran with a descriptive-analytical approach, relying on Persian sources and a critical view of previous researches. The findings of the study suggests that, despite the conformity of this structure with Iranian bureaucratic traditions that greatly facilitated the work of the Iranian and the Mongol bureaucrats, the different background of bureaucracy and the particular situation of Iran led to major difference in the functioning, overall life and fate of the Tamma in Iran, compared to other parts of