Cowpea plants co-infected with the wilt pathogens Fusarium oxysponun f. sp. tracheiphilum (Fot) or f. sp. phaseoli (Fop) with the Sunn-hemp mosaic virus (SHMV) showed greater losses in total fresh weight, leaf area, length of main axis than comparable healthy plants, or plants infected with any one of the pathogens alone. The changes were shown to be consistent in the two cultivars tested. In cv. 'California Blackeye' co-infection with Fot and SHMV caused the death of most of the plants within 28 days of inoculation. There was no consistent pattern in the changes in virus titre with time in the two cultivars. It is suggested that the interaction of either fungus with SHMV in cowpeas may be a synergistic relationship.