An outbreak of coccidiosis by Isospora icterus (I. icterus, Upton & Whitaker, 2000) in captive Campo Troupial (Icterus jamacaii) (Gmelin, 1788) at the Wild Animals Triage Center (IBAMA, Belo Horizonte, Brazil) is described. Clinical history and the necropsy findings documented diarrhea with diffuse necrotic enteritis. Sporulated oocysts (n = 100) had a bilayered wall, were subspherical, and measured 30.1 (27.5–32.5) μm in length and 28.5 (26.2–30.0) μm in width. A polar body but no micropyle was present and the length/width ratio was 1.1 (1.00–1.2). Each oocyst contained two ellipsoidal sporocysts measuring 17.6 (15.0–20.0) μm in length and 12.9 (12.5–15.0) μm in width, with a length/width ratio of 1.4 (1.2–1.5), and with Stieda and sub-Stieda bodies. Each sporocyst contained four sporozoites with granular sporocyst residuum. Oocysts were compatible with those from I. icterus, previously described in Campo Troupial.