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  Background and Objectives: Ticks play an important role in different diseases of human and animals in Iran. With respects to the reports on the occurrence of Borreliasis and CCHF in Ardabil province, an attempt was made to study fauna and geographical distribution of two families of ticks, Ixodidae and Argasidae in different parts of the province.

  Methods: Within the scope of present study, several villages were randomly selected. From the study area during four different seasons, the total number of 2080 ticks were collected and identified according to the national systematic keys.

  Results: The collected ticks were categorized in 10 species from two families, and 3 genera. They were as follow: hard ticks from Ixodidae families, Hyalomma, Rhipicephalus and Heamaphysalis were found in 65.5%, 34.3% and 0.2% respectively. In Argasidae family, Ornithodoros comprise (97.2%) and Argas (2.8%). In Hyalomma genus, Hy. marginatum (16.9%) and Hy. aegyptium (%0.3) had the most and least density, respectively. Among soft ticks, Ornithodoros lahorensis (97.2%) had the highest number during autumn and winter. The main important hosts were sheep, cow, poultry, goat, buffalo and camel. Cypermethrin was evaluated against Argas persicus and O. lahorensis and results compared to that of Kordistan, Lorestan and West Azerbaijan strains. Results showed that Meshkinshar strain exhibits 1.7 fold susceptible to this insecticide than other strains at the LD₅₀ level.

Conclusion: Results of this study is useful for study on the biodiversity of ticks and their frequency. It is medically important for controlling disease and may result in reduction of disease transmission.