Abstract: The clinical data of 31 cases of halo nevus were analysed. The biopsy specimens of 7 cases were examined under light microscopy and 4 of them under electron microscopy. Of 31 patients with halo nevus 14 (45.1%) associated with vitiligo. Usually there was a dense lymphocytic infiltration around or between the nevus cells of halo nevus. Nevus cells often showed evidence of damage and destruction, and disappeared ultimately. The number of Langerhans cells seemed to be increased in the skin involved by halo nevus and the melanocytes absent in the epidermisobserved under electron microscopy.