BACKGROUND: Atopic dermatitis (AD) is a chronic inflammatory skin disease. It is caused by immunological abnormalities, abnormalities of the skin barrier, and environmental/genetic factors. We did a preclinical trial to identify the effects of the 633-nm light- emitting diode (LED) and 830-nm LED for AD-like lesions in NC/Nga mice. METHODS: AD-like skin lesions were induced by topical application of Dermatophagoides farinae extract on the skin of 5-week-old NC/Nga mice for 2 weeks, and then was treated with 630-nm or 830-nm LED for 1 week. We identified any therapeutic effects on AD using modified SCORAD index, skin biopsy, and measurements of both transepidermal water loss (TEWL) and proinflammatory cytokines. RESULTS: Both of 630-nm and 830-nm LED treatment groups showed significantly reduced SCORAD indices and TEWLs at the end of treatment, compared to the non-treatment group. In addition, the levels of proinflammatory cytokine levels in both of the LED treatment groups were significantly decreased compared to those in the non-treatment group. CONCLUSION: These results show that 633-nm and 830-nm LED treatments can improve -like lesions in NC/Nga mice.