Sweet potato virus disease (SPVD) is the name used to describe a range of severe symptoms in different cultivars ofsweet potato,comprisingoverallplantstunting combinedwith leaf narrowingand distortion,and chlorosis,mosaic orvein-clearing. Affected plants of various cultivars were collected from several regions of Uganda. All samplescontained the aphid-borne sweet potato feathery mottle potyvirus (SPFMV) and almost all contained the white?y-borne sweet potato chlorotic stunt closterovirus (SPCSV). SPCSV was detected by a mix of monoclonal antibodies(MAb)previouslyshowntoreact onlyto aKenyanisolate ofSPCSV,butnot byamixtureofMAb thatdetected SPCSVisolates from Nigeria and other countries. Sweet potato chlorotic ?eck virus (SPCFV) and sweet potato mild mottleipomovirus (SPMMV) were seldom detected in SPVD-affected plants, while sweet potato latent virus (SPLV) wasnever detected. Isolates of SPFMVand SPCSVobtained by insect transmissionstogether induced typical symptoms ofSPVD when graft-inoculated to virus-free sweet potato.SPCSValone caused stunting and either purpling or yellowingof middle and lower leaves when graft-inoculated to virus-free plants of two cultivars. Similarly diseased naturallyinoculated ?eld plants were shown consistently to contain SPCSV. Both this disease and SPVD spread rapidly in asweet potato crop.