The present study describes a new isosporoid coccidian parasite from the bananaquit Coereba flaveola, in Brazil. This new species is similar to I. cagasebi, but it can be distinguished by the size and shape of Stieda and susbstieda bodies. Isospora coerebae n. sp. oocysts are spheroidal to sub-spheroidal, 24.8 × 23.3 μm, with a smooth and bi-layered wall, ~1.2 μm. Micropyle, oocyst residuum and polar granule are absent. Sporocysts are elongate ovoidal, 17.9 × 10.9 μm. Stieda and substieda bodies are present. Sporocyst residuum is present and sporozoites have a posterior refractile body.