Systemic lupus erythematosus is an autoimmune connective-tissue disorder with a wide range of clinical features, which predominantly affects women, especially from certain ethnic groups. Diagnosis is based on clinical assessment supported by investigations, including the finding of autoantibodies. Treatments range from antimalarial agents to corticosteroids and immunosuppressive agents. This Seminar draws attention to advances in the epidemiology, genetics, cardiovascular risks, lupus nephritis, CNS disease, the antiphospholipid syndrome, assessment of disease activity and damage, and pregnancy related and quality of life issues. New therapeutic approaches, such as biological agents and mycophenolate mofetil, will also be discussed.