In the root zone of plants nitrogen-fixing bacteria are able to synthesize a wide range of biologically active compounds, including compounds of phytohormonal nature. We have previously studied the ability of soybean nodule bacteria Bradyrhizobium japonicum to synthesize such extracellular phytohormones as auxins, cytokinins and abscisic acid. It is known that phytohormones with growth stimulation activity (gibberellins) have wide spectrum of influence on physiological processes in plants. Gibberellins cause stem elongation in plants, which is based on the cell spreading and increased mitotic activity. The aim of this work was to study the synthesis of gibberellic extracellular compounds by biotechnological strains of nitrogen-fixing symbiotic bacteria B. japonicum. The objects of research were highly effective biotechnological strains of B. japonicum: UCM В-6018, UCM В-6035 (Ukrainian Collection of Microorganisms) and KC19, KC23 (IAMAM NAAS Collection of Microorganisms). All B. japonicum strains were grown in a liquid yeast extract mannitol medium in periodic conditions. Phytohormones with gibberellic activity were isolated with ethyl acetate in the ratio 1:1 (v/v) at pH 2.5. The obtained extracts were evaporated at 40−45 °C. Dry residue was dissolved in ethanol and used for physical and chemical analysis of phytohormones. The total ability to synthesize gibberellin by rhizobia was evaluated in specific phytotest. Qualitative and quantitative determination of gibberellins was performed by high performance liquid chromatography (HPLC) method using a liquid chromatograph Agilent 1200 (Agilent Technologies, USA) and mass spectral detector Agilent G1956B. For comparison, standard solutions of gibberellins GA3, GA4 and GA7 (Sigma-Aldrich, Germany) were used. The quantity of synthesized gibberellins was expressed in μg per 1 g of absolutely dry biomass (ADB). By the phytotests results it was shown the presence of gibberellic nature compounds in cultural liquids of all studied soybean nodule bacteria B. japonicum. Results obtained by HPLC have confirmed the phytotest results about presence of extracellular compounds with gibberellic activity in all rhizobia strains. Among active biotechnological B. japonicum strains the largest amount of gibberellins was synthesized by strains B. japonicum UCM B-6018 (161.1 μg/g ADB of GA3 and 5.1 μg/g ADB of GA4) and B. japonicum KC23 (201.2 μg/g ADB of GA3 and 4.3 μg/g ADB of GA4). Slightly less amount of gibberellins was synthesized by another active strain B. japonicum UCM B-6035 – 136.7 and 5.3 μg/g ADB respectively. In the supernatant of B. japonicum strain KC19 was detected GA3 (85.0 μg/g ADB) but not detected GA4. Also trace amounts of GA7 were found in all extracts. It should be noted, that all the strains produced much bigger amount of GA3 than GA4 and GA7. It is GA3 that has the highest biological activity in plants among gibberellic compounds. Thereby obtained data prove the ability of soybean Bradyrhizobia to synthesize phytohormones gibberellins. Besides there is reasons to say about possible perspectives of using effective strains for stimulation seeds germination and raising the productivity of soybean plants as preparations not only with nitrogen fixing activity, but also with stimulation of gibberellin production activity.