The antistress protective action of two structural analogs of GABA, fenibut and its salt with citric acid (fenibut citrate, citrocard, RGPU-147), has been studied using a model of chronic stress caused by seven-fold 24-h deprivation of paradoxical sleep phase at an interval of 24 h between the deprivations. It is established that fenibut and fenibut citrate produce a protective action by (i) reducing the intensity of emotional disorders in the open-field test and elevated plus maze test, (ii) decreasing cognitive disorders in the tests for conditioned avoidance response and extrapolatory deliverance; and (iii) limiting stress reaction due to a decrease in the intensity of adrenal hypertrophy, thymus involution, and stomach mucous membrane ulceration. Fenibut citrate surpasses fenibut in the intensity of antistress protective action.