Literature sources have been surveyed concerning the two-spore white button mushroom (Agaricus bisporus) affected by phytopathogenic bacteria. Yield losses and decrease of fruit body quality caused by bacterial spots and rot under the conditions of industrial cultivation have been estimated. It has been established that the button mushroom affection at the second fruiting break can reach 55% that causes the yield shortage of more than 5 kg from 1 m2 and financial losses of 1000 Euro for each growing cycle. The bacteria development intensity was found to depend on growing by shelves. The most favourable growing conditions were observed on the lower shelf; the number of affected mushrooms was 1145-1526 mushrooms 1 m2 or 95.4% that resulted in the yield losses of 9.5 kg/m2. The loss of mushrooms from bacterial rot reached 1.5 kg/m2. The degree of affection of fruit bodies was estimated by the developed scale. According to the scale 22.7% of mushrooms are fit for realization in fresh or canned form (the infection degree 5-10%).