The effect of post-harvest treatment with Fitomag on the quality and structural parameters of plum fruits of the varieties Stanley and Udlinionnaya was studied. It has been established that the treatment with this preparation is effective for storing plum fruits of the studied varieties in a normal atmosphere and ensures the preservation of their biological value, structural characteristics and commercial qualities (freshness, juiciness, firmness, pulp turgor). The yield of standard fruits after three months of storage due to the treatment with Phytomag is more than 92%, the natural weight loss is 1.1-1.2 times less than the control.