A filamentous virus was isolated from naturally infected soybean, Glycine max, at the International Institute of Tropical Agriculture, Ibadan, Nigeria. The virus induced infection that ranged between symptomless to mild mosaic and mottle on soybean under glasshouse conditions. It was readily sap-transmissible to 11 out of 14 members of the Leguminosae, the members each of the Chenopodiaceae and Cucurbitaceae and four members of the Solanaceae. Its assay host was Chenopodium amaranticolor which produced chlorotic local lesions on inoculated leaves 5-10 days and inoculation. Its propagation hosts were Nicotiana clevelandii and N. megalosiphon. On the basis of host range, transmission, particle morphology and serology this virus has been identified as an isolate of cowpea mild mottle virus.