Primal problem of vegetable growing is constant supply of the population with all types of vegetables, including green cultures. Green cultures are vegetables that have high nutritional value and precocity. However they often are infected by phytopathogenic microorganisms already at initial stages of ontogenesis at cultivation in closed soil conditions. It leads to emergence of disjointed shoots, deterioration of growth and development of plants and loss of quality. Now in the Republic of Belarus a number of biological substances on the basis of bacteria Bacillus was developed. They are used against diseases of plants of mushroom and bacterial etiology. However there is not information about influence of bacteria on quality of products of green cultures. The aim of the work was studying of influence of two strains of bacteria Bacillus that were introduced in peat substrate on efficiency and quality of lettuce. Two strains of bacteria Bacillus were used in the work. They were selected from the soil. The strains are Bacillus subtilis M9/6 and Bacillus amyloliquefaciens 23TM that have high antagonistic activity to a wide range of phytopathogens. Cultivation of plants carried out in containers of 250 ml under light installations with illuminating intensity 13-15 thousand luxury and lasting irradiating of 14 hours before technical ripeness of lettuce. It was established that the application of strain Bacillus subtilis M9/6 (in concentration 106 cells/ml, 10 ml/l of substrate) and the strain Bacillus amyloliquefaciens 23TM (5 ml/l of substrate) in substrate before sowing increased nutrition value of lettuce. Dry matter content, water-soluble carbohydrates (mono - and disaccharides) content and vitamin C content increased. The bacterial strain B. amyloliquefaciens 23TM also promoted accumulation of vitamin B2. The content of nitrates in lettuce leaves decreased on 50,3% and 39,1%, respectively. It was shown that the application of bacteria in substrate before sowing of crop has a greater influence on quality of lettuce, than watering of shoots.