The results of investigations on the coccidian parasites of three species of penguins ( Pygoscelis antarctica , P. papua and P. adeliae ), nesting at Livingston and King George Island (South Shetland Islands, the Antarctic) are presented. Three coccidian para− sites: Eimeria pygosceli Golemansky, 2003, Eimeria sp. and Isospora sp. were identified in faecal samples from 360 examined birds. The total prevalence of coccidian parasites was high: about 35% in all of examined penguins. No host specificity was observed. It is attributed due to the close phylogenetic relations, common habitats and nesting territories, similar feeding and reproductive biology of the three penguin species. In more than 20 specimens of investigated penguins a high intensity of oocysts in their guano was observed (80–220 oocysts in one microscopic field at magnification of 150×) an indirect indication of the negative role of the coccidian infections on penguin populations.