The Siberian Tatars, who lived in the Tobolsk province in the 19th century, had a syncretic character of culture. It was shamanism, a pre-Islamic religion characteristic of the North of Western Siberia. However, the traces of another religion – Zoroastrianism – and, in general, the influence of Iran (Persia) introduced by the Siberian Bukharians, have not yet been studied. The purpose of the research is to analyze the metric books of the Kazan yurt of Tobolsk province for 1831–1855, to substantiate the traces of Iranian-Zoroastrian influence on the ideas of the Siberian Tatars. The results of the study of the texts of the metric books revealed a serious layer of Iranian influence: the old Persian language, images of “Iranian drums”, the presence of business connections in Persia, etc. The entries in the metric books about “Iranian drums” as ritual objects are combined with the mention of Sufis and the text of the Koran, Islamic prayers. The religious role of the “drums” corresponds to the ancient Sufi dafs, modern Khorezmian and Ob-Ugric tambourines. Such variant of syncretism was a natural phenomenon. This was due to the peculiarities of Islam in Western Siberia, ethnic processes and assimilation of the Siberian Bukharians and the Ob Ugrians. In addition, Iranian Zoroastrianism was already known in the North of Western Siberia, when objects of Iranian origin arrived at the temples of the Ob Ugrians.