Nine isolates of Xanthomonas oryzae pv. oryzae were isolated from symptomatic rice leaf samples collected from different rice-producing areas at Damietta governorate in Egypt during 2009 growing season. The isolates were identified on the basis of morphological, physiological and biochemical tests.  The identity of these isolates were confirmed by the Biolog system and pathogenicity test. Virulence of isolates and cultivars reactions were investigated under experimental conditions. The abilities of isolates to cause lesions with different lengths across the cultivars Giza 176 and Sakha 101were interpreted as virulence. Although typical bacterial blight symptoms were visible for all isolates on the two cultivars, diversity in virulence was observed among isolates. Isolates that were consistently associated with high or low virulence were statistically differentiated. Eleven Egyptian rice cultivars were inoculated by two isolates of X. oryzae pv. oryzae to identify the resistance response to this pathogen. Among tested cultivars, no resistant cultivars were found. According to used scale, all cultivars ranged from moderately susceptible to susceptible.