Leaf yellowing and rolling with slight crinkling was observed in radish plants in Oman, indicative of a begomovirus infection. Viral sequences from radish were 99% identical to sequences of Tomato yellow leaf curl virus (TYLCV) and Chilli leaf curl virus (ChiLCV), from Oman. No beta-or alpha-satellites were detected. Infectious clones were developed and infectivity analyses of isolated viruses were done in a model host Nicotiana benthamiana. Both viruses, when inoculated separately, produced typical symptoms; however, symptom severity increased when these viruses were co-inoculated. Southern analyses confirmed that virus accumulation was high when both viruses were inoculated as compared to independent inoculation. Realtime qPCR analyses showed that copy number of both viruses was 1 X 10 6 copies when N. benthamiana plants were inoculated with either TYLCV or ChiLCV; however, the copy number increased to 1 X 10 8 copies when the two viruses were co-inoculated together in N. benthamiana.