Abstract: This paper reports a pair of twin sisters who developed nearly in the same time, on the same location of the body lesions of lupus ery-thematosus profundus which were identified by the clinical features and histopathogical findings. Their blood group and HLA typing were completely identical. The homozygous probability was 98.87% by calculation, so it was considered that they were homozygous twins and the hereditary factor played certain role in the pathogenesis of the disease. The same type of anti-blood vessel endothelial cell antibody was found in the peripheral blood of both patients. A brief discussion was made around the possible function of this antibody.