The percentage of the infected area of cabbage leaves was utilized to study the virulence factors of sixteen Xanthomonas campestris pv. campestris (Xcc) isolates associated with black rot symptoms on cabbage (Brassica oleracea). Lipopolysaccharide and adenosine kinase production, cell adhesion, xanthan gum production, and viscosity were all compared for different isolates. The tested strains were divided into three statistical groups, five strains (Xcc4, Xcc7, Xcc11, Xcc13 and Xcc16) gave the highest measurements after incubation, six strains (Xcc1, Xcc2, Xcc8, Xcc10, Xcc14 and Xcc15) had small measurements and five strains (Xcc3, Xcc5, Xcc6, Xcc9 and Xcc12) showed an intermediate value. Finally, increasing the production of lipopolysaccharides, adenosine kinase, cell adhesion, and xanthan gum increases the virulence of Xanthomonas strains, whereas the viscosity of the isolates is not considered a factor affecting disease severity or virulence.