In the experiments were investigated the changes of the concentration of some mono- and disaccharide's in the flower buds of the frost resistant and frost sensitive apricot cultivars due to the frost treatment in the different stage of dormancy. Among sugars analysed, sucrose, glucose, and fructose were detected in each point of time. Concentration of glucose and fructose didn't differ from each other in any treatment and at any point of time. Concentration of glucose and fructose doesn't increase during the winter. Sucrose's concentration in the buds of frost resistant cultivar increased from November until January and then rapidly dropped down. In case of frost sensitive cultivar the concentration of sucrose continuously decreased during the winter. The degree of the resistance against frost is rather related to the proportion between sucrose and monosaccharides explained by so-called sugar-index.