Introduction. Despite the apparent connection of the existing neurological disorders and changes in the psycho-emotional sphere with sleep disorders in patients with chronic mercury intoxication (CRI), these relationships remain the least studied in the clinic neurointoxications. The study aimed to establish a connection between neurophysiological, biochemical, and psychopathological indicators in patients with occupational chronic mercury intoxication and insomnia. Materials and methods. Thirty-six patients took part in the examination in the remote period of CRI. The average age of patients in this group was 50.7±1.05 years, with an average work experience of 14.7±1.05. The authors carried out a psychological examination to determine the levels of depression, anxiety, asthenic state, computed electroencephalography (EEG), cognitive evoked potentials (CEP), polysomnography, the level of neurotransmitters. Results. The study showed that asthenization, when exposed to mercury, occurs due to a decrease in the limbic-hypothalamo-reticular complex activity (the presence of equivalent dipole sources of pathological activity in the area of diencephalic formations (thalamus, hypothalamus) in 56.2±5.6% of cases. The study showed a decrease in activity cerebral cortex, confirmed by weakening the coherent connections of the α-range in the occipital, central and frontal leads according to the data of coherent EEG analysis and changes on the part of the CEP. There was a direct correlation between the level of total sleep time and the serotonin level (rs=0.45), an inverse relationship between the level of depression and histamine level (rs=-0.56). Conclusion. The studies carried out to make it possible to establish the mechanisms of insomnia disorders in chronic mercury intoxication, which cause a weakening of the tone of the cerebral cortex and changes in neurotransmitter metabolism, as well as disorders of the reticular system with limbic structures. The study showed a close direct relationship between neurophysiological, psychological, and biochemical parameters in implementing insomnia in patients with chronic mercury intoxication.