Nesidiocoris tenuis Reuter has good potential as a biological control agent for Bemisia tabaciGennadius on tomato. There is a possibility that this predator also controls Tomato yellow leaf curl virus TYLCV transmission by B. tabaci. In this study, four treatments were compared: 1 50 N. tenuis/plant 3 times released 150 NR , 2 25 N. tenuis/plant 2 times released 50 NR , 3 5 N. tenuis/plant 2 times released 10 NR , and 4 insecticide treated as a conventional control, to evaluate the inhibitory effect of the predator on TYLCV in greenhouse tomato. The infection rate for TYLCV was significantly lower in 150 NR than 10 NR during the experiment. Additionally, the B. tabaci density was significantly lower in 150 NR and 50 NR than 10 NR. These results suggest that TYLCV transmission by B. tabaci was inhibited by N. tenuis. However, it is difficult to control TYLCV only by N. tenuis or insecticides, because the infection rates for TYLCV and rates of viruliferous B. tabaci of TYLCV were 89 100% and 70 80%, respectively, at the end of all treatments. Therefore, N. tenuis is recommended for use as a biological control agent in integrated pest management for TYLCV.