In this work, we conduct a comparative morphological study of the diversity of glial cells in the tissues and organs of the mediastinum of newborn rats using immunohistochemical markers. In rats aged 1 day, the innervation of the organs of the cardiovascular, digestive, and respiratory systems was studied in frontal sections through the cardiopulmonary complex (using the neural immunohistochemical protein marker PGP 9.5 and glial markers GFAP and S100β). In the mediastinal organs (SRDS), two type of glia — astrocyte-like cells and neurolemmocytes — were revealed. Astrocyte-like cells are similar to the glia of the CNS, neurolemmocytes or Schwann cells are similar to the glia of the PNS. Some were found in the neuropil of the Aurbach's ganglionic plexus of the enteric nervous system of the esophagus, and others were detected in the ganglia, microganglia, in the large trunks, and bundles of the nerve plexuses of the parasympathetic and sympathetic divisions of the somatic and autonomic nervous system. Among the neurolemmocytes in the SRDS, the following populations were identified: myelin-forming Schwann cells, neurolemmocytes of unmyelinated nerve fibers, neurolemmocytes of the Remak fascicles of the main terminal synaptic plexus, as well as satellite or capsule cells of neurocytes of the intramural ganglia. According to the modern knowledge, glia plays an important role in the functioning of vital organs in the norm, as well as in the preservation of the integrity of neural structures in pathology. Therefore, the results obtained are important for biomedical research on the development of new therapies aimed at changing the functional status of glial cells.