The use of innovative cereal cultivation technology based on the application of plant growth-promoting bacteria together with undersown legume is gaining particular importance, especially in organic cereal cultivation, which is expected to provide raw material with high protein content under changing climate conditions. To address this, a field study was conducted in 2019-2021 to determine the effects of plant growth-promoting rhizobacteria (PGPR) and phosphorus-releasing bacteria applied together with an undersown crops on nitrogen content, total protein and total protein yield of spring barley grown in organic agriculture. Two factors were investigated in the experiment. A:  bacterial formulation: control (without bacterial formulation), plant growth-promoting rhizobacteria (PGPR) (Bacillus subtilis, Bacillus amyloliquefaciens, Pseudomonas fluorenscens), phosphorus-releasing bacteria (Bacillus megaterium var. phosphaticum, Arthrobacter agilis). B: Undersown crops: control (no undersown crops), red clover, red clover + Italian ryegrass, Italian ryegrass.  In spring barley grain, nitrogen content was determined and total protein content and total protein yield were calculated. The results obtained allow us to conclude that the development of an innovative technology of spring barley cultivation based on the application of PGPR bacteria together with an undersown red clover or a mixture of red clover and Italian ryegrass will ensure the obtaining of grain with high total protein and total protein yield. Such grain meets high quality parameters, and is a valuable raw material for the production of groats and flakes that are functional foods from organic cultivation.