A total of 647 birds of 146 species representing 41 families from localities in Kenya, Tanzania and Zaire were examined for blood parasites. A total of 242 (37.2%) birds harbored either single or multiple infections of Haemoproteus (16%), Leucocytozoon (14%), Plasmodium (5.4%), Trypanosoma (1.7%), microfilaria (2.9%) or a variety of babesioids and haemogregarines (4.3%). Occurrence of blood parasites was greatest in Zaire and least in Kenya; the occurrence of the different genera varied markedly between areas and between bird families.