This review is given on the origin and interrelationship of blackgram and greengram: the symptoms, mode of transmission, and host range of important diseases, namely: mungbean yellow mosaic virus, leaf crinkle virus, leaf curl virus, mosaic mottle virus, Cercospora leaf spot, powdery mildew, root and stem rots, bacterial leaf spot and halo blight. The screening for resistance, sources of resistance, including interspecific hybridization, and induced mutations, as well as the genetics of resistance are treated along with suggestions for future breeding strategies of these crops.