The aim of this study was to evaluate the bacterium Rahnella aquatilis (Ra) for protection of bean plants against common blight disease caused by Xanthomonas axonopodis pv. phaseoli (Xap). Xap isolates were isolated from a naturally blighted leaves of bean plants grown in Assiut governorate. The blight symptoms were produced by all three isolates, but the isolates differed in their degree of the pathogenicity. Xap1 was the most virulence one against bean plants. The effect of Ra against common blight of bean plant was tested. In vitro studies, Ra exhibited inhibitor effect against the pathogen. Under greenhouse and field conditions, beanvariety “Giza 6” treated by Ra resulted in marked disease suppression. Ahigh decrease of the disease was correlated with a reduction of the bacterial multiplication. In physiological studies, bean plants treated by Ra exhibited higher phenolic compounds contents and higher activity of peroxidase (PO) enzyme than untreated plants. In conclusion, application of Ra was effective and could be recommended for controlling the bean common blight disease.