The aim of our research was morphological assessment of neurons in the globus pallidus after 28-day administration of dexamethasone. The experiments were carried out on adult Albino Swiss mice males. It was found that prolonged administration of this glucocorticosteroid causes degenerative changes in neurons of the globus pallidus (shrinkage of nerve cells, increased stainability of nucleus and cytoplasm). We also observed increased numbers of glial cells in this area of the brain.