Moalla, M., A. Ahmed, O. Hammoudi and I.D. Ismail. 2020. Effect of the bacterial strain Bacillus subtilis FZB27 in controlling cucumber mosaic virus (CMV) in pepper plants grown under greenhouse conditions. Arab Journal of Plant Protection, 38(2): 130-136. This study aimed to evaluate the effect of bacterial strain Bacillus subtilis FZB27 on growth and productivity improvement of pepper plants infected with cucumber mosaic virus (CMV) using three different applications (treated seeds, irrigated with bacterial suspension, treated seeds + irrigated with bacterial suspension). Pepper seeds were soaked for 12 hours in a suspension of B. subtilis FZB27 with concentration of 9×10 9 cfu/ml. Ten days later, the seedlings were irrigated with 20 ml of the same concentration suspension of B. subtilis FZB27, then inoculated with CMV one week after transplanting. The results showed that, there was a significant increase in: (i) Plants height and roots length of the bacterial treated plants compared to the healthy control, and significant increase in the height and roots length of the infected and bacterial treated plants compared to the infected control, with best results obtained from the treated seeds + irrigation with bacterial suspension treatment, with no significant differences among the different treatments, and (ii) Increased fruits weight and the root fresh and dry weight and vegetative growth of the bacterial treated plants compared to the healthy control, and significant increase of the CMV-infected and bacterial treated plants compared to the infected control, with best results obtained from the treated seeds + irrigation with bacterial suspension treatment, with no significant differences among the treatment methods.