NZB/NZW mice spontaneously exhibit autoimmune disease similar to that seen in human systemic lupus erythematosus (SLE). We demonstrated that total lymphoid irradiation (TLI) reversed well expressed disease in 6-mo-old NZB/NZW females with a prolongation in survival, decrease in proteinuria, and decrease in anti-DNA antibodies as compared to control animals. Few side effects were observed in the treated group. TLI also prolonged survival in animals with advanced renal disease. These findings suggest that TLI may have application to the treatment of human SLE.