The prevalences of 2 species of isosporid coccidia are reported from 3 of 6 steppe polecats, Mustela eversmanii Lesson, 1827, trapped in an alpine meadow of the Haibei area, Qinghai Province, China, during the summer of 2010. The structures of the sporulated oocysts allowed us to determine that they represented 2 forms not reported since their original description in Kazakhstan by Svanbaev (1956) as Isospora eversmanni and Isospora pavlovskyi. However, the evidence continues to accumulate that Isospora species infecting mammals that have thick walls and do not have a Stieda body on their sporocysts should be transferred to Cystoisospora Frenkel, 1977; thus, we have emended the names to reflect that transfer. In addition, we provide detailed mensural data and photomicrographs of sporulated oocysts, both lacking in their modest original descriptions, to help illustrate the differences seen between these species. We also submitted phototypes of a sporulated oocyst of each species to the United States National Parasite Collection (USNPC), and deposited a symbiotype host in the Qinghai-Tibet Plateau Museum.