From 2009 to 2012 collaborators of the Mongolian Vertebrate Parasite Project funded by the U.S. National Science Foundation mounted 4 major expeditions into south and southwestern Mongolia covering low- and high-altitude habitats consisting of desert, desert-steppe, and montane biomes. Both ecto- and endo-parasites were obtained from all of the approximately 4,000 mammals collected during this work. The present report contains a summary of the coccidian parasites of gerbils (Meriones Illiger 1811) collected during the warm-weather months in the Gobi and Altai regions of Mongolia. A total of 171 gerbils of 3 species from 22 separate localities were examined for coccidia. Coccidian oocysts were identified from 21 gerbils, but those found in one of those gerbils were probably pseudoparasites of the host from which they were recovered. From the remaining 20 gerbils, 7 morphotypes of Eimeria and 1 morphotype of Isospora Schneider 1881 were identified. Four of the 7 morphotypes of Eimeria were attributed to new species, which are described herein. In order to identify any apparent epidemiological trends, χ² tests were performed to identify correlations between infection with species of Eimeria or Isospora and host species, sex, infection with helminths, and year and month of capture. The only significant (α  =  0.10) correlation found using a χ² test was that between host species and infection by Eimeria spp. (P  =  0.07); oocysts of Eimeria spp.