This study conducted during 3 years period (2002-2004). Tick sampling was randomly carried out from domestic animals during seasonal activity of ticks from six provinces of Iran. 2170 ticks from 151 cattle , 629 sheep, 336 goats and 32 camels were collected proin 30 prosseces with a mean number of 1.9 tick per animal. 209 Dermacentor ticks collected from six provinces( Kordestan, Ardebil, East Azarbaiejan, Zanjan, Khorasan and Semnan) that included 23% of collected tick population in those provinces. The diversity of Dermacentor is restricted to three species; D.niveus (50%), D.marginatus (27%) and D.raskemensis (23%). The maximum occurance of D.raskemensis , D.niveus, D.marginatus, were occurred in provinces of Semnan, Khorasan and Kordestan, respectively. It can be concluded that livestock had almost different pattern of tick species in any localities thus distribution of D.raskemensis , D.niveus, D. marginatus, has been confirmed this matter.