Isospora coerebae Berto, Flausino, Luz, Ferreira Lopes, 2010 is a coccidian protozoan described from bananaquits Coereba flaveola (Linnaeus, 1758), on Marambaia Island, which is located on the southeastern Brazilian coast. In this current work, I. coerebae is identified from C. flaveola in a protected area close to Marambaia Island, but on the mainland, establishing a new location of parasitism, in addition to providing a preliminary genotypic characterization via sequencing of two regions of the mitochondrial cytochrome c oxidase subunit 1 (COI) gene. Its oocysts are sub-spherical, 24.4 22.9 m, with smooth, bilayered wall, ~1.7 m thick. Micropyle, polar granules and oocyst residuum are absent. Sporocysts are elongate ovoidal, 17.6 10.5 m. Stieda body prominent and rounded and sub-Stieda body short and wide. Sporocyst residuum is composed of scattered granules of different sizes. Sporozoites are vermiform with a prominent posterior refractile body. The oocysts of the current work are morphologically equivalent to the original description of I. coerebae, which have a typical and easily identifiable morphology, mainly in the Stieda and Sub-Stieda bodies. The two sequenced gene regions of the COI gene approximated I. coerebae to Isospora spp. from Southeastern Brazil, but also from Isospora spp. from passerines of North America, Europe and Asia. Although there is a small overlap between the two genic regions sequenced in the current work, it is estimated that the longer COI sequence, which was recently designed and still not widespread, should show better phylogenetic results in the future.