Background: The pathogenesis of alopecia areata (AA) remainsincompletely understood. Basic research has established AA as a T cellmediated autoimmune disease. Different cytokines may play a role in AA. TNF-α has been shown to be inhibitory to hair follicle growth in in-vitro studies suggesting that it may play an important role in AA. However, there are many reports of failure of anti-TNF-α agents in treating AA with reports of worsening or induction of AA which made the role of TNF-α doubted and needs further investigations.Aim of work: This thesis was conducted to assess the presence ofTNF-α in lesional skin of AA and to review its possible role in AA.Patients and methods: Thirty six patients with localized and recentonset AA and 12 age and sex matched healthy controls were included in the study. A 5-mm punch skin biopsy was taken from lesional and non lesional skin of every patient, as well as from the normal skin of each individual in the control group for PCR quantitative analysis of TNF-α.Results: The level of TNF- α in lesional skin biopsies was significantlyhigher than in non lesional skin biopsies of patients as well as controls'biopsies. Also, TNF-α level in non lesional biopsies of patients wassignificantly higher than the level in controls' biopsies. When correlating TNF-α level in lesional, non lesional and controls' biopsies, it was neither affected by the subject's age and gender nor the duration, site and extent of lesion.Conclusion and recommendations: We can conclude that skin ofearly localized cases of AA has a high level of TNF-α (a normal inhibitor of hair follicle growth in-vitro). This high level may point to the important role of TNF-α in AA. Further studies should be conducted to detect the level of TNF-α in long standing AA and the more severe cases of AA (i.e. AT and AU) and studies to investigate the unexpected failure of anti-TNF-α agents in treating AA and the paradoxical occurrence of AA while on anti- TNF-αagents.