Eight hundred thirty wild vertebrates from 3 states in the Savanna Biogeographical Region of eastern Colombia were examined for blood parasites. Of these, 229 were positive (28%) with a total of 262 infections. Findings included: hemogregarines (4%) in lizards and marsupials; malaria (2%) in lizards; filariae (7%) in rodents, marsupials, carnivores, monkeys, and lizards; piroplasms (6%) in rodents, opossums, deer, and an ocelot; and trypanosomes (11%) in marsupials, deer, mon- keys, an anteater, and rodents. The parasites were identified when possible, or described insofar as we were able with the material avialable. The marsupial hemoparasite complex in eastern Colombia is similar to that of eastern Brazil, and the range extensions of several parasites reflect the zoogeographical history of their hosts. Blood films from a collection of 830 wild mammals and reptiles from eastern Colombia revealed foci of malaria, piroplasms, filariae, hemogregarines, and trypanosomes. The para- sites were identified to species whenever pos- sible. The animal hosts came from the Orinoco watershed, part of the Savanna Biogeographi- cal Region (Fig. 1) stretching from Guiana westward across southern Venezuela to the base of the Colombian Andes. Triatome- carried trypanosomiasis is endemic in the area (D'Alessandro et al., 1971), but information on hemoparasites in the wild animal popula- tion is scarce. The published blood parasite surveys include about 400 mammals and 350 birds (Marinkelle and Grose, 1968; Renjifo et al., 1952).