[Objectives]  To detect the effects of the southern rice black-streaked dwarf virus (SRBSDV) on the resistance              of white-backed planthopper (WBPH) resistant rice varieties to the WBPH. [Methods]  8 1st-2nd instar WBPH nymphs were placed on individual rice seedlings to evaluate the resistance of different rice varieties to WBPH, according to the international standard. Each seedling was infected with 2 older nymphs that had been fed with the virus and had passed the cycle period to evaluate the resistance of WBPH-resistant rice varieties to SRBSDV. Different life-stages of WBPH were placed on SRBSDV-infected rice to study the effects of SRBSDV-infection of WBPH-resistant, rice varieties on the feeding selectivity, feeding capacity, survival rate, fecundity and hatchability of WBPH. [Results]  Rice varieties with moderate, resistance and high resistance to WBPH were highly susceptible to SRBSDV, with an incidence rate of more than 93.55%. Non-virus WBPH nymphs were inoculated onto both healthy and SRBSDV-infected, WBPH-resistant rice plants. After 48 hours, healthy plants had 1.33-5.33 nymphs/plant whereas SRBSDV-infected plants had 24.00-46.00 nymphs/plant. WBPH prefered to feed on SRBSDV-infected plants, but there was no significant correlation with the resistance of rice to WBPH. After WBPH adults had fed on healthy and SRBSDV-infected rice plants for 48 hours, the average amount of honeydew was 1.13-9.55 mg/adult and 2.97-17.35 mg/adult, respectively. The average amount of honeydew secreted by WBPH feed on SRBSDV-infected, WBPH-resistant, rice varieties was significantly different and higher than that healthy plants. The survival rate of WBPHs on rice with resistance or high resistance was between 15%-44.05%, whereas their survival rate on plants infected with SRBSDV was significantly higher; > 69.21%. The non-virus WBPH can reproduce normally on on WBPH-resistant rice varieties that are infected with SRBSDV, and egg production and egg hatching rate are significantly higher on infected plants than on healthy plants. [Conclusion]  SRBSDV infection of WBPH-resistant rice improves the feeding, survival and reproduction of the WBPH. WBPH-resistant rice varieties are not necessarily resistant to SRBSDV and the resistance of such varieties is decreased by SRBSDV infection.