Between May 2012 and July 2013, 4 eastern hognose snakes (Heterodon platirhinos) were collected from Arkansas (n  =  2) and Oklahoma (n  =  2), U.S.A., and examined for coccidians. Feces from a single H. platirhinos from Arkansas, U.S.A., were found to be contain oocysts of Caryospora lampropeltis Anderson, Duszynski, and Marquardt, 1968. Oocysts obtained from host feces were spheroidal to slightly subspheroidal with a rough, colorless, and bilayered wall, measure 23.5 × 22.8 µm, and with a length/width (L/W) ratio of 1.0; both micropyle and oocyst residuum were absent, but a prominent polar granule was present. Sporocysts were ovoidal, 16.8 × 12.8 µm, L/W of 1.3; a prominent Stieda and sub-Stieda body was present; a sporocyst residuum was present and composed of numerous spheroidal granules dispersed into small and large granules. Sporozoites lie lengthwise and parallel in a semispiral in the sporocyst; a spheroidal anterior refractile and a posterior refractile body are present; a single nucleus is located between the 2 refractile bodies. To our knowledge, this represents the first report of a caryosporan reported from H. platirhinos as well as the only known coccidian from this host. A summary of hosts of C. lampropeltis is provided.