At first, humans determined the time of day and night by observing the sun and then by making blue, sundials, and sand clocks. In addition, another means of determining time was playing the flute, which reminded people of sunrise and sunset. With the adoption of Islam by Iranians, sundials were created in mosques to determine the time of prayer and call to prayer. With the arrival of mechanical clocks from the Safavid period, sundials were replaced by mechanical clocks that were repaired and made by foreigners for the king and courtiers. From this time on, clocks were installed in different parts of the shrine of Imam Reza (AS) that were made by Iranians themselves, and this has led to the creation of a profession called clockmaking in the administrative organization of the shrine. The present research, using a descriptive-analytical method and relying on (unpublished) documents of the organization of the Holy Shrine of Razavi, seeks to answer the question of what was the reason for the importance of the use of clocks and the position of clockmakers in the administrative organization of this shrine during the Safavid and Afsharid periods? The results of the present study indicate that the documents of the administrative organization of Astan Quds Razavi, as one of the most important first-hand sources that contain unique information and knowledge about the watchmaking industry in the Razavi Holy Shrine, as one of the first religious places to install mechanical clocks, were important in order to facilitate determining the time and performing the obligatory prayer with the help of Iranian experts familiar with various sciences and industries.