During fauna studies, thirty-six wild mammals were collected in adjacent areas of Itapecuru River and Environmental Preservation area of Inhamum, state of Maranhão, Brazil. They were sampled for ectoparasites. The following specimens of the order Rodentia and its respective ectoparasites were identified: Akodon sp. (Androlaelaps sp. and Laelaps sp.), Oecomys sp. (Androlaelaps sp. and Amblyomma cajennense), Oligoryzomys sp. (Androlaelaps sp. Laelaps sp. and Amblyomma sp.) e Oryzomys megacephalus (A. cajennense). In Calomys callosus no ectoparasite was found. It was observed infestation in the order Didelphimorphia as follows: Didelphis marsupialis (Androlaelaps sp., Laelaps sp. and larvae of Diptera Cyclorrhapha); Gracilinanus sp. (Laelaps sp. and larvae of Diptera Cyclorrhapha), Monodelphis domestica (Poplygenis (Polygenis)), Cummingsia sp., Amblyomma sp. and Androlaelaps sp.). Marmosa sp. e Thylamis sp. had no ectoparasites. From the captured hosts 56% were infested, 82% and 44% rodents and marsupials, respectively. Mites from the family Laelapidae presented the great diversity of hosts and genus.