Background/Aim. Pterygium internum presents a significant epidemiological problem. Its etiopathogenesis is still unclear. After surgical removal it shows great tendency to recidives. The aim of this paper was to investigate connection between histopathological characteristics (inflammation presence, vascularization degree and fibrinoid changes) of pterygium and its clinical characteristics (duration, size, pterygium grade, presence of Fuchs' spots and recidives) and determine indicators for recidives prediction. Metods. We analyzed the material taken from 55 patients operated by Arlthi's method. The samples were colored by using standard histochemical methods: hematoxylin-eosin (HE), trichrome Masson painting, Gomora reticulin and PAS technique. Results. Pterygium was mostly covered by epithelium resembling conjunctival, while in the frontal cap region it showed the morphology of plate-layer cornea epithelium. The structural basis of the epithelium was composed of continuous basal lamina and continuous adhesive fibres underneath. This adhesive basis showed fibrinoid changes in the form of oval islands of various size, parallel to convexity of pterygium, or in the form of unified focus. The number, caliber and type of blood vessels showed a pronounced variability. Duration of pterygium and its size were in negative correlation with intensity of inflammation, without statistical significance. Pterygium with a longer period of develepment had negative correlation with the degree of vascularization (p > 0.05). The presence of Fuchs' spots showed a statitistically significant positive correlation with the degree of vascularization (p < 0.05). The intensity of fibrinoid changes was higher in pterygium with Fuchs' spots and in those which recurred (p > 0.05). Conclusion. Histopathological analysis of pterygium morphological shapes is a good basis for the prediction of recidives, which present the greatest problem in the treatment of this widely spread disease.