The effect of bacteria Bacillus subtilis strain 26D in combination with stress phytohormones – salicylic (SA) and jasmonic (JA) acids, on the content of H₂O₂, transcriptional activity of genes of pathogen-induced (PR) proteins (PR-1, PR-6, PR-9 ) and a change in the spectrum of potato (Solanum tuberosum L.) leaves proteins in connection with development of resistance to the causative agent of late blight – oomycete Phytophthora infestans (Mont.) de Bary against the background of a lack of moisture in soil have been investigated. Plants grown from microtubers on a soil substrate in containers treated with B. subtilis suspension (10⁸ cells / ml) and with a mixture of bacteria with SA (10^-6 M), JA (10^-7 M), SA + JA (1:1 ratio), then were infected with P. infestans zoospores (10⁷ spores / ml) and cultivated under artificial drought conditions. Some of treated plants were left uninfected. A significant decrease in degree of P. infestans leaf infection was revealed under influence of B. subtilis treatment in combination with JA. An increase in potato resistance was mediated by a stimulating effect on the concentration of H₂O₂ and on the transcriptional activity of PR-protein genes in plant tissues. Using two-dimensional electrophoresis we have revealed the differences in the content of 19 polypeptides in the pI range 4.0 to 9.0 and MW range 30 to 125 kDa. On the basis of cluster and factor analyzes, it was shown that treatment of B. subtilis plants most significantly changes the spectrum and relative content of individual proteins in both healthy and infected plants. Probably, stress phytohormones activate plant defense mechanisms aimed at the generation of Н₂О₂ and preventing the change in the spectrum of protective proteins induced by symbiotic bacteria. The most significant factor determining the change in the proteome of P. infestans infected potato plants against the background of drought is the combination of B. subtilis with JA.