The present paper, deals with study of the resistance against two antibiotics in a phytopathogenic bacterium Xanthomonas campestris (Pammel) Dowson. Colonies resistant to the vancomycin appeared even in the highest concentration used (256 meg/ml.). For the tylosin in concentrations higher than 128 mcg/ml resistant colonies did not appear. So, the results show that vancomycin follows the "single-step" model and the tylosin follows the "multiple-step" resistant scheme.