Emerging infectious diseases, 2009; 15 (12)A renaviruses are segmented negative-strand RNA vi- ruses. Their natural hosts are various rodent species. The virus family comprises several human pathogens caus- ing hemorrhagic fever, namely Machupo, Guanarito, Junin, Sabia, and Chapare viruses in South America, and Lassa and Lujo viruses in Africa (1–3). In addition, Africa har- bors arenaviruses that are not linked with human disease: Mobala, Ippy, Mopeia, and Kodoko viruses (4–7). We con- ducted a systematic search in wildlife in Tanzania to iden- tify new African arenaviruses.