Sera from humans, birds, domestic and wild animals, from 17 localities in four ecological zones of Nigeria were tested for neutralizing antibody to Orungo virus. A total of 1197 human sera were tested, of which 277 (23.1%) were positive for Rungo antibody. The highest prevalence (34.2%) was found in the northern Guinea Savannah zone. The prevalence in the other zones were 29.9% in the Southern Guinea Savannah, 24.3% in the Derived Savannah and 17.0% in the rainforest. Significant differences in antibody prevalence were found between, the wet forested area and the drier Savannah regions, with an increasing trend from the wetter to the drier zones. Over 50% of sheep, with about 24% of monkeys and 14% of cows tested were positive for Orungo virus N antibody. It is suggested that man and animals are involved in the transmission cycle of Orungo virus in Nigeria, possibly with Aedes spp. mosquitoes acting as an important vector.