Striped bass, Morone saxatilis (Moronidae), collected from several rivers in South Carolina, U.S.A., were found to be infected with heterophyid metacercariae whose morphology was consistent with Ascocotyle (Phagicola) nana on the basis of descriptions from the literature and via comparison with reference specimens of metacercariae from largemouth bass, Micropterus salmoides (Centrarchidae), a known intermediate host for A. nana. Morphology of metacercariae from both fish species was similar and partial sequencing of their 18S ribosomal DNA gene confirmed that metacercariae from both fish belonged to the same heterophyid species. Young-of-the-year striped bass were not infected and over 65% of the population sampled (N  =  39) age 1 yr and older were infected with up to 49 metacercariae per gram of somatic muscle. Mid-line red muscle (lateralis superficialis) had a significantly higher density of metacercariae than epaxial and hypaxial white muscle. Some metacercariae showed signs of degradation or were dead, but in the majority of specimens little to no host reaction occurred and numerous worms were observed moving within their cysts. Morone saxatilis was thus considered to be a suitable intermediate host for this parasite. This is the first report of a species in the family Moronidae acting as intermediate host for A. nana, which emphasizes the need to examine more Perciforme fishes in known areas of endemicity for this parasite to better assess the complexity of its biology, life cycle, and its potential for human pathogenicity.