Neonatal lupus erythematosus (NLE) is an autoimmune disease whose major findings are subacute cutaneous lupus erythematosus (SCLE) skin lesions and congenital heart block. Babies have maternal anti-Ro/SSA, anti-La/SSB, or anti-U1RNP autoantibodies. Anti-Ro/SSA are the predominant autoantibodies, having been found in about 95% of cases. The autoantibodies pass through the placenta from mother to child. Skin disease resolves at about the time that maternal autoantibodies can no longer be detected in the baby. NLE therefore provides the strongest clinical evidence that autoantibodies are involved in at least some manifestations of lupus erythematosus, but there is as yet no definitive evidence implicating autoantibodies in the disease process. Skin disease usually begins after birth, is transient, and does not result in scarring. Cardiac disease begins in utero, and the heart block is almost always permanent. Many babies require pacemakers, and about 10% die from complications related to cardiac disease. In some cases, transient liver disease or thrombocytopenia have been observed. Individuals who had NLE usually have healthy childhoods but may develop autoimmune disease in adulthood. Whether the later development of autoimmune disease is a common or an unusual event is not yet known. Mothers of babies with NLE may be asymptomatic initially, but with time usually develop symptoms of autoimmune disease. The most typical constellation of symptoms in our group of approximately 30 mothers of babies with NLE is that of Sjögren's syndrome. Most babies exposed to anti-Ro/SSA autoantibodies during gestation will not develop NLE. There is no test to determine prospectively which babies will be affected. Treatment during gestation is still controversial and, if attempted, should be reserved for fetuses with potentially life-threatening disease. Treatment after birth consists of topical management for skin disease and pacemaker implantation, if necessary, for heart block. Systemic steroids may be given for serious internal disease.