Survey and collecting of the Iranian tydeoid mite fauna over the last 40 years, including the present data, have resulted in a collective list of 43 species of Triophtydeidae, Iolinidae and Tydeidae, covering 12 of the 30 provinces. During 2008–2010, a faunistic survey of tydeoid mites was made in Razavi Khorasan Province of Iran. As a result, four tydeoid species were stated as new for fauna of the study area and one species (Tydeus calabrus) — new for the Iranian fauna. Three other ones (of the genera Neopronematus and Tydeus) are new to science. The new taxa are described and a key to the species of Neopronematus is proposed. A checklist of Iranian tydeoids is provided.