Influence of the synthetic analogues of brassinosteroids (epibrassinolid and homobrassinolid) on germination of cabbage (Brassica oleracea L.) seeds of different physiological state was presented. Seeds were sorted on the fraction according to the chlorophyll content in the membranes and then the seeds were made worse in quality by means of accelerated aging. Research results showed that infusion of epibrassinolid and homobrassinolid phytohormones into dry white cabbage seeds before the beginning of the accelerated aging delayed the development of deteriorative process under the unfavorable conditions. On the physiological level the seeds treated with phytohormones showed the higher germination rate and total germination in comparison the untreated control group. Stabilization of cell membrane proved to be one of the mechanisms responsible for the protective influence of exogenous brassinosteroids. Research results proved that the efficiency of brassinosteroids depended on the initial physiological quality of seeds in the following way: the lower seeds maturity caused the higher sensitivity to the conditions of accelerated aging and the higher effect of exogenous treatment