Abstract: In this study, the serum levels of DNA in the patients with lupus erythematosus are determined by diphenylamine method and compared with those of the healthy subjects. The results showed that the serum levels of DNA (43.5μg/ml) in the patients with LE were higher than those in the healthy subjects (33.4μg/ml). The levels of serum DNA in patients of LE seem to be correlated with the activity of the disease. The determinations of serum DNA are considered to be of value in studying the pathogenesis of LE.