Blood smears were examined from 143 penguins of four species (Aptenodytes patagonicus, Eudyptes chrysolophus, E. schlegeli, and Pygoscelis gentoo) from Sub-antarctic Macquarie Island and Heard Island. No blood parasites were reported. The vectors of Hepatozoon albatrossi (reported from three species of albatross) are probably shared by penguins, and it is suggested that the latter are not susceptible to infection with this protozoan. Cestodes of the genus Tetrabothrius were present in large numbers in the intestines of 17 Antarctic petrels (Thalassoica antarctica), and evidence is presented indicating that euphausiid crustaceans may be intermediate hosts.