The paper deals with the investigation of the relationship between chronic inflammation in the subepithelial layer and histological changes of the epithelium of radicular cysts. Histological examination of 60 radicular cyst specimens was carried out with the aim to define this relationship. The stratified squamous epithelium with a variety of histological changes was found in 58 specimens. A high degrees of chronic inflammation in the subepithelial layer was also recorded. Histological changes of the epithelium correlated to the degree of inflammation in the subepithelial layer of radicular cysts.