Electroencephalographic methods were used to study effects of the preparation of the exogenous heat shock protein with molecular mass 70 kDa (Hsp70i/Hsc70) on the time characteristics of sleep and waking, brain temperature, peripheral vasomotor reactions and thoracic muscle contractile activity after the 5-hour sleep deprivation in pigeons (Columba livia). The microinjections of Hsp70i/Hsc70 were performed into the third brain ventricle after the end of sleep deprivation. It was shown that Hsp70i/Hsc70 eliminated the disturbances of sleep-wake cycle and evoked a decrease in the thoracic muscle contractile and brain temperature during the first hour of postdeprivation period. During the following hours Hsp70i/Hsc70 evoked an increase in the total time of deep sleep and a decrease in the total time of rapid-eye-movement sleep. We suppose that the protective effects of Hsp70i/Hsc70 could be associated with its capacity to weaken the activity of the hypothalamo-hypophyseal-adrenal axis and to enhance the stress-limiting function of non-rapid-eye-movement sleep.