Fecal samples from 20 Caucasian tree squirrels, Sciurus anomalus (Gmelin, 1778) Güldenstaedt, 1785, were collected in Turkey during February and March, 2004, and all 20 were infected with a single species of coccidia, Eimeria serbica. Sporulated oocysts are ellipsoidal, 27.5 × 17.5 (21-34 × 15-20) with a length:width ratio (L/W) of 1.6 (1.4-1.8); they lack a micropyle and oocyst residuum, but 0-2 polar granules may be present. Sporocysts are ellipsoidal, 11.9 × 6.9 (10.5-14 × 6-7.5) with a L/W of 1.7 (1.5-2.1); a Stieda body and sporocyst residuum are present. © American Society of Parasitologists 2005.