AbstractDipetalonema caudispina(Molin, 1858) andD. gracile(Rudolphi, 1809) (Filarioidea: Onchocercidae) are two of six known species of filarial nematodes that parasitize Neotropical non-human primates. Adult filariae were collected from the thoracic and abdominal cavities of 38 of 44 specimens ofSapajus macrocephalus(Spix, 1823) and nine of ten specimens ofCebus albifrons(Humboldt, 1812) (Primates: Cebidae), distributed in the Yavarí-Mirín river basin and used locally for human consumption. Co-occurrence ofD. caudispinaandD. gracileis reported for the first time, with a prevalence of 18.5% (10 of 54 hosts examined). Our finding ofD. caudispinaandD. gracilein cebids from the Peruvian Amazon constitutes a new geographical record for both filariae, two new host records forD. caudispina,and the first report ofD. gracileinS. macrocephalus. In addition, we provide morphometric data forD. caudispina, complementing the original description, as well as scanning electron microscopy details on the structure of the area rugosa and number of caudal papillae in males.