Background: Diabetes mellitus (DM) is a significant healthcare problem concern worldwide that has different pathological effects on the body tissues and organs. A number of oral soft tissue abnormalities have been associated with DM by various reports. L-carnitine (LC) is an essential nutrient that is present in almost all animal species, microorganisms and plants.The scope of this study is two-fold: 1) to investigate degenerative changes in the epithelium of the diabetic rat tongue, and 2) to test the hypothesis that (LC) attenuates epithelial cell degeneration. Materials and methods: Thirty adult male albino rats were divided into 3 equal groups: group I; (control group), group II; (diabetic group): diabetes was induced by a single intraperitoneal injection of streptozotocin in a dose of 35 mg/kg and group III; (LC) rats were treated as in diabetic group and injected intraperitoneally by (LC) at a dose of 300mg/kg b.w/day for 4 weeks. By the end of the experimental periods all animals were sacrificed and the tongue of all rats were dissected and processed for light and immunohistochemical examinations. Results: Examination of dorsal surface of diabetic rats' tongues revealed numerous filliform papillae with evidently disturbed orientation and inclination. Some of them appear notched; others were destructed with desquamation of its epithelial covering. Dorsal surface of rats' tongues of (LC) group revealed almost normal direction, distribution and structure of the papillae and taste buds. Immunohistochemical examination of Ki67 expression of the control group showed significant decrease in Ki67 positive immunoreactivity, indicating less proliferative changes. While (LC) treated group revealed expression of Ki67, that statistically having no significant difference with control group