MicroRNA-155 has been implicated in several autoimmune diseases, including experimental autoimmune encephalomyelitis and rheumatoid arthritis, due to its activity against a wide range of immunological gene targets. Overexpression of miR-155 may represent a hallmark feature in Alopecia areata (AA) disease pathogenesis and across multiple autoimmune conditions. It could potentially reflect and or influence the activation of T cells in autoimmune diseas. The present work aims is to assess serum level of miRNA-155 in patients with AA. MiR-155 level was identified by real-time polymerase chain reaction (PCR) in 30 patients with AA and 30 individuals as healthy controls. Results: There was a statistically significant increase in serum miR-155 level in patients than in controls. Conclusion: Serum level of miR-155 was significantly higher in patients with AA than controls, which indicated its role in the pathogenesis of AA.