Tiles are artistic handicrafts and tilework has been a principal means of decorating architecture in Iran through the Islamic period. By tradition, the tile makers and decorators used to sign their work at intermittent periods and this made the Islamic tiles unequivocal evidence for documenting the forgotten history of the buildings and monitoring the changes in their architectural decorations. Although many of the historic monuments in Islamic lands have been studied in detail based on their tilework and other architectural decorations, the Holy Shrines in Iraq have not been thoroughly studied as there is no detailed document on the history of their decorations. Field research indicates that these religious monuments have been adversely affected by the embedded interferences in their architecture during the past two decades; therefore, these Islamic heritage sites have not remained intact owing to their gradual destruction or abrasion and in complete disregard of their artistic merits and historical significance. This research aims to provide an introduction to the tilework of the Holy Shrine of Imam Ali (AS) by studying the surviving remains of the original tiles of this shrine, documenting the tilemakers and the tile decorators’ signatures and picturing the tiles from the early Ilkhanid to the late Qajar period. The results indicate that the shrine’s tile decorations have been added, replaced and restored frequently over time and their craftsmen are of Iranian and Iraqi (esp. from the city of Karbala) origin. The tiles’ quality and techniques of decoration reveal that some had been produced in Iran and then transferred to the city of Najaf and some were made in Iraq by the Iranian tilemakers. In addition, the commissioners have been Iranian, Ottoman or Iraqi.