Forty-nine adult and 14 immature Great Plains narrowmouth toads (Gastrophryne olivacea) from Johnson and Somervell Counties of northcentral Texas were examined for parasites. Sixty-four percent of the toads were infected with one or more species of parasites. New host records are reported for an isosporan similar to Isospora neos, and for Cylindrotaenia americana. The most common parasite in G. olivacea was the nematode, Cosmocercoides dukae. Prevalence was high among the adult G. olivacea (82%); however, none of the immature toads were infected.