This current study reports a new isosporoid (Apicomplexa: Eimeriidae) species parasitizing rufous-collared sparrows, Zonotrichia capensis, kept in captivity located in the mountainous region of Rio de Janeiro, Brazil. Isospora ticoticoi n. sp. oocysts are spherical to sub-spherical, 23.3 × 22.4 μm, with smooth, bilayered wall, ~1.2 μm. Micropyle and oocyst residuum are absent, however, sometimes, polar granules are present. Sporocysts are ellipsoidal, 17.0 × 10.8 μm. Stieda and substieda bodies are present. Sporocyst residuum is present, sporozoites have one refractile body and a nucleus.