A large number of extra- and intramural ganglia in humans and animals exist. All pathways of central regulation of vegetative functions and peripheral reflex pathways pass through them, providing coordinated automatic activity of many organs and tissues. It is well known that sympathetic and sensory neurons are affected in the early stages of diabetes. Patients with diabetes often have autonomic neuropathies. They suffer from disorders of the cardiovascular system and vessels functions, from disorders of the thermoregulatory and pupilomotor functions. These disorders may be the result of the superior cervical ganglion neurons functional defects. This ganglion involves in homeostasis, innervates pineal gland, thyroid, vascular plexus, vestibular system, pupillary, carotid bodies, salivary and lacrimal glands, innervates vessels of the skull and brain. The superior cervical ganglion’s postganglionic axons also innervate the heart. However, disorders of the synaptic transmission in superior cervical ganglion neurons in diabetes remain insufficiently studied to date. Therefore, this article is about the physiological properties of the superior cervical ganglion neurons and their pathological changes in diabetes mellitus. The works about synaptic neurotransmission disorders in superior cervical ganglion neurons of animals with experimental diabetes mellitus are analyzed.