Using electrophysiological methods, the effects of total sleep deprivation on thermoregulatory characteristics of the febrile reaction (brain temperature, peripheral vasomotor reaction, contractile activity of the pectoral muscle), the process of rehabilitation of somatic functions, and temporal characteristics of wakefulness and sleep during the endotoxaemia caused by the bacterial endotoxin lipopolysaccharide (LPS) in pigeons (Columba livia) were studied. It was shown that sleep deprivation during the period of the augmentation of non-rapid-eye-movement sleep in result of the LPS injection evoked a decrease in latency of the fever development and fever duration and caused a more pronounced rise of the brain temperature and the level of contractile muscular activity in comparison with the effects of LPS. The period after sleep deprivation was characterized by a more prolonged recovery of the level of contractile muscular activity and temporal characteristics of sleep and wakefulness and more prolonged compensatory rebound of non-rapid-eye-movement sleep in comparison with the effect of sleep deprivation alone. Thus the realization of sleep deprivation during endotoxaemia evoked a decrease in latency of the fever development and the reinforcement of fever; and an increase in latency of the restoration of physiological functions.