|Abstract||Three species of chewing lice, 11 species of sucking lice; and 28 species of fleas are recorded from mammals in Missouri. Of these, seven species of sucking lice (Hoplopleuraacanthopus, Hoplopleura hesperomydis, Hoplopleura sciuricola, Neohaematopinus sciuri, Neohaematopinus sciurinus, Neohaematopinus sciuropteri, and Solenopotes ferrisi) and one species of flea (Doratopsylla blarinae) represent new state records. From 1993 to 1995, 773 individual mammals were examined for ectoparasites in southeastern Missouri. One species of chewing louse, 6 species of sucking lice, and 11 species of fleas were recovered from 18 of the 21 mammal species examined. Ctenophthalmus pseudagyrtes was recovered from more mammal species (6) than any other flea species; and the white-footed mouse, Peromyscus leucopus, was parasitized by more flea species (5) than other hosts examined. Except for H. sciuricola, which was recovered from two congeneric species of tree squirrels, each species of louse was confined to a separate host species.