PURPOSE: Atopic dermatitis is a chronic relapsing inflammatory skin disease that results from allergic reaction. Steroid therapy has become a major therapeutic modality for treatment of atopic dermatitis. Several immunomodulatory therapies have been tried for atopic dermatitis. In this study thymopentin therapy was performed and its clinical effects and laboratory results were evaluated. METHODS: Atopic dermatitis with typical clinical symptoms were included in this study. Twelve patients were treated with subcutaneous injection of thymopentin ( (Imupentin ) at a dose of 1 mg/kg, three times per week for eight weeks. Clinical scores were measured by Hanifin scoring system before and at the end of the treatment. General hematologic laboratory tests such as hemoglobin, hematocrit, WBC count, neutrophil percentage, lymphocytes percentage and eosinophil percentage as well as blood IgE level were conducted at the same time. RESULTS: The clinical severity of atopic dermatitis patients was markedly improved by thymopentin therapy. The clinical severity score improved by 85.5%. Three patients showed complete remission of clinical status at the end of thymopentin therapy. Hemoglobin, hematocrit, WBC counts, neutrophil percentage, and lymphocyte percentage were not affected by the thymopentin therapy. Eosinophil percentage and blood IgE level were significantly reduced statistically. CONCLUSION: Thymopentin therapy is an effective immunomodulatory therapeutic modality in atopic dermatitis. Thymopentin decreased eosinophil percentage and blood IgE levels without other hematologic changes.