Tomato (Lycopersicon lycopersicum L.) is one of the major vegetable crops grown world widely. The biotic stress caused by Tomato Yellow Curl Leaf Virus (TYLCV) is a serious problem that can lead to 100% economic loss. TYLCV is caused by begomovirus genus of the family giminivirdae which is a single stranded DNA. Resistance to begomoviruses is an essential breeding aim for cultivated tomato. Numerous resistance genes have been characterized in tomato wild species and introgressed into cultivated tomato species. Six major resistance genes had been identified; these are Ty-1 to Ty-6. In the present study, ten tomato genotypes harboring one or more of three TYLCD resistance genes (Ty-1, Ty-2 and Ty-3) were tested by PCR and assessed for their resistance against TYLCV/ChiLCV using modified assessment scale in two locations in Oman. Also, the effect of virus infection on yield, plant height in cm and chlorophyll estimation using SPAD meter were studied. This study was done to test the hypothesis that tomato genotypes containing Ty genes are resistant against begomoviruses and therefore have better growth and productivity than tomato genotypes lacking Ty genes. The results demonstrated that GS12 which have no resistant genes was susceptible to TYLCV/ChiLCV as it showed the highest virus infection percentage. Genotypes T2a and T3 containing Ty-1, Ty-2 and Ty-3 genes were tolerant. T10 and T6 genotypes both had low resistance. The rest genotypes had a moderate resistance. The resistant T3 genotype showed the highest yield weight. The resistant T2a genotype obtained the highest chlorophyll estimation. The susceptible GS12 genotypes showed the lowest yield and there was a noticeable reduction in the chlorophyll estimation which was expected as yellowing is one of the major symptoms of TYLCD. The virus infection did not affect the plant height in this experiment.