The phytogeographical distributions of Haemaphysalis juxtakochi, Ixodes pararicinus and Otobius megnini in Argentina are described from material collected mainly from 1978 to the present. H. juxtakochi was found in the northwestern area of the Amazonian domain and in the Chaco, Espinal and Pampean provinces of the Chaco domain. It was detected on Mazama spp., Tapirus terrestris, dog, cattle and on the vegetation. Most findings of I. pararicinus were from mountain rangeland, where it was found on cattle and in a lesser extent on horses. Ticks from Argentina classified as Ixodes ricinus were probably I. pararicinus. O. megnini was detected on cattle an sheep in the Andean Patagonian domain and in the Monte, Chaco and Espinal provinces of the Chaco domain. This tick is considered typical of arid and semiarid conditions, however the findings from the Espinal province where from areas with an annual rainfall over 900 mm.