The ticks reported in Paraguay, which are here reviewed, can be categorized as 'endemic or established' (Argas persicus or a sibling species, Ornithodoros hasei, O. rostratus, O. rudis, O. talaje/O. puertoricensis, Amblyomma aureolatum, Am. auricularium, Am. brasiliense, Am. cajennense, Am. calcaratum, Am. coelebs, Am. dissimile, Am. dubitatum, Am. incisum, Am. longirostre, Am. nodosum, Am. ovale, Am. pacae, Am. parvum, Am. pseudoconcolor, Am. rotundatum, Am. scutatum, Am. tigrinum, Am. triste, Dermacentor nitens, Haemaphysalis juxtakochi, H. leporispalustris, Ixodes loricatus, Rhipicephalus microplus, and Rh. sanguineus), 'probably endemic or established' (Ar. miniatus, Ar. monachus, Am. argentinae, Am. humerale, Am. naponense, Am. oblongoguttatum, Am. pseudoparvum, I. aragaoi/I. pararicinus, I. auritulus, I. luciae), or 'erroneously reported from Paraguay' (O. coriaceus, Am. americanum and Am. maculatum). Most Paraguayan tick collections have been made in the Chaco phyto-geographical domain, in the central part of the country. Argas persicus or a related species, Am. cajennense, D. nitens, Rh. microplus and Rh. sanguineus are important parasites of domestic animals. Ornithodoros rudis, Am. aureolatum, Am. brasiliense, Am. cajennense, Am. coelebs, Am. incisum, Am. ovale and Am. tigrinum have all been collected from humans. In terms of public health, the collections of Am. cajennense and Am. triste from humans may be particularly significant, as these species are potential vectors of Rickettsia rickettsii and Ri. parkeri, respectively.