Background: Glial cell line-derived neurotrophic factor (GDNF), produced by basal cell keratinocytes, is a neurotrophic factor that plays diverse developmental roles and together with its cognate receptor (GFR Rα-1) are distal members of the transforming growth factor- β super family. To date, their expression pattern in lichen planus is still unknown. Objectives: To investigate the immunohis to chemical expression patterns of GDNF and its cognate receptor (GFRα-1) in lichen planus and compare the results with the normal skin from healthy controls. Patients and Methods:Twenty patients with lichen planus were examined in addition to twenty age and sex matched healthy subjects (the control group). Punch biopsies from lesional and normal healthy skin were performed. Sections were examined using immunohis to chemical staining methods for GDNF and GFRα-1proteins expression patterns expression analysis. Results: There was strong GDNF protein expression in the basal cell keratinocytes and moderate gene expression in the spinous layer and weak gene expression in the granular layer of the healthy skin. In contrast, in lichen planus, GDNF protein expression was absent in the basal cell keratinocytes and lower reaches of the spinous layer. Weak gene expression was noted in the upper reaches of the epidermis. In both healthy and lichen planus skins, the expression of GFRα-1in the adnesal structures showed no differences.Conclusion: The altered GDNF protein expression may contribute to the pathogenesis of lichen planus