This research compares the common illustrated THEMES in manuscripts from Ilkhanid AND Timurid periods. In general, the THEMES in Iranian painting are divided into seven categories of history, religion, animals, epic, lyrical love, realism, decoration, in which the THEMES of history, religion, animals AND epic have more commons in both periods. In this research, only these four THEMES AND the reasons to consider them will be surveyed. The purpose of this research is to study the goals of illustrating the same THEMES in the manuscripts of the mentioned dynasties. The question of this research is: What are the differences AND similarities between the images in the illustrated manuscripts of the Ilkhani AND Timurid eras? This research is conducted by using descriptive-analytic method. The results of this research indicate that portraiture of historical manuscripts of Ilkhanid era is wider than in Timurid Dynasty due to the declaration of the Mughal commitment to the Iranian heritage. In terms of RELIGIOUS theme in the Ilkhanid period, non-Islamic THEMES, such as Christian, Buddhist, AND Jewish issues, have been used along the Islamic issues, for example, regarding Christian matters, the reason is the presence of Christians in the top government of Ilkhanid. In Timurid era, the presence of non-Islamic issues was paled but Islamic issues, especially the Shi’ I, was highlighted. The third common theme is animals, which seems to be more visible in Timurid era. The reason of this claim is the similar manuscripts of Kalilah wa-Dimna, Ajaib al-Makhlughat by Qazwini AND manuscripts with hunting scenes in two periods, AND also some unifoliate pictures AND Mantiq al-tayr manuscripts in Timurid era. The difference between the mentioned periods regarding using epic theme in illustrated manuscripts almost refers to details. In addition, the boom of this theme is more in Timurid period concerning the more number of illustrated shahnamas. Finally, it can be concluded that similarities between common THEMES in these eras are more than their differences.