The prevalence of 7 species of Coccidia is reported from 137 Colorado pikas, Ochotona princeps, collected on Mt. Evans, Clear Creek County, Colorado, during the summers of 1968, 1969, and 1971. Identification of the parasites was based on the structure of the unsporulated oocysts which, at least for those species that have been described to date from North American pika hosts, are highly distinctive for most species. Photographs illustrate the differences in size, shape, and form of the oocysts of the various species. A key to the Coccidia of pikas, based on the descriptions of sporulated oocysts, is presented.