Abstract The genus Setaria is known worldwide for parasiting wild and domestic mammals, with 43 species registered, of which five occur in the American continent. The objective of this study was to characterize the occurrence, morphology and morphometry of S. labiatopapillosa in B. taurus and B. bubalis in Marajó Island, Brazil. Carcass inspections of 420 cattle were carried out in two slaughterhouses in Pará. The nematodes were found on the white and serous viscera of the small intestine, being cleaned and discussed for analysis by light microscopy and scanning electron microscopy. The morphological and morphometric characteristics are compatible with S. labiatopapillosa parasitizing both species, with a prevalence of 25% (B. bubalis) and 24% (B. taurus). Information obtained by scanning electron microscopy was added to the description of the species, in addition to expanding the distribution of this parasite in the national territory.