Sera from various wild ruminants co-existing in the same habitats with cattle had haemagglutination-inhibition (HI) antibodies as high as those in the cattle. Sera from wildebeest (Connochaetes taurinus), kongoni (Alcelaphus cokei), Thomson's gazelle (Gazella thomsonii), eland (Taurotragus oryx) and the African buffalo (Syncerus caffer) had titers ranging from 64 to 128. Zebra (Equus burchelli), bushbuck (Tragelaphus scriptus), warthog (Phacochoerus aethiopicus), and oryx (Oryx spp.) sera were negative to the HI test. It was suggested that some of the wild ruminants with high titers could be a possible reservoir of parainfluenza-3 virus.