This paper gives a list and maps of distribution of 26 tick species occurring in Iran (Argas persicus, Argas reflexus, Ornithodoros canestrinii, Ornithodoros erraticus, Ornithodoros lahorensis, Ornithodoros tartakovskyi, Ornithodoros tholozani, Boophilus annulatus, Dermacentor marginatus, Haemaphysalis concinna, Haemaphysalis concinna erinacei, Haemaphysalis concinna, Haemaphysalis inermis, Haemaphysalis punctata, Haemaphysalis sulcata, Hyalomma aegyptium, Hyalomma detritum, Hyalomma dromedarii, Hyalomma excavatum, Hyalomma rufipes glabrum, Hyalomma savignyi, Hyalomma schulzei, Ixodes crenulatus,Ixodes ricinus, Rhipicephalus sanguineus, Rhipicephalus bursa). Hyalomma species are identified according to the school of Delpy. Most of the material (41.644 specimens) has been collected by the entomological staff of the Institute of Parasitology and Malariology of Iran and only two species (O. erraticus, H. inermis) have not been observed by the Institute. Four species: Boophilus calcaratus (Bir., 1895), Haemaphysalis numidiana Neum., 1905, H. cinnabarina punctata (Can. and Fanz. 1878) and H. cholodkovskyi Olenev, 19288, previously reported from Iran, are considered synonyms of B. annulatus (Say, 1821), H. erinacei Pavesi, 1884, H. punctata Can. and Fanz., 1878 and H. sulcata Can. and Fanz., 1878 respectively. Three species: Dermacentor marginatus, Ixodes crenulatus and Ixodes ? sp. are new for Iran.