The aim of this study was to examine the effects of variation of organic (yeast extract, soybean flour and peptone) and inorganic nitrogen sources (NaNO₂, KNO₃ and (NH₄)₂HPO₄) in medium for biobactericides production by Bacillus subtilis ATCC 6633. The antibacterial activity of samples against the reference strain Xanthomonas campestris ATCC 13951 and different Xanthomonas strains isolated from cabbage, kale and cauliflower was determined in vitro by disc-diffusion method. Following statistical analysis, it was concluded that both nitrogen sources have statistically significant effect on biobactericides production under applied conditions whereby the influence of inorganic nitrogen is more pronounced. The results of Duncan's test suggested that the highest biosynthesis of antibacterial compounds was achieved in both media, with or without yeast extract, when NaNO₂ was used as an inorganic nitrogen source. The results from this study can be used in further research to improve biobactericides production by the reference Bacillus subtilis strain.