We conducted a formal survey of small-mammal ectoparasite diversity in Iowa. We examined 166 small mammals and documented 54 species of parasitic arthropods present on 12 species of mammals. Ectoparasite species richness was greatest for Blarina brevicauda (northern short-tailed shrew), Microtus ochrogaster (prairie vole), Peromyscus maniculatus (deer mouse), and Peromyscus leucopus (white-footed mouse). Immature (larvae and nymphs) Dermacentor variabilis (American dog tick) were collected from P. leucopus, M. ochrogaster, Reithrodontomys megalotis (western harvest mouse), and Zapus hudsonius (meadow jumping mouse). The fleas Epitedia wenmanni and Orchopeas leucopus, potential vectors of sylvatic plague bacilli, were found on Mus musculus (house mouse), white-footed mouse, and deer mouse. We document 21 new ectoparasite host records for North America and 115 new host locality records for ectoparasites in Iowa.