Systemic lupus erythematosus, an autoimmune disorder which predominantly affects young women, is frequently complicated by renal involvement. Lupus nephritis (LN) is characterized by immune-complex mediated glomerular and tubulointerstitial inflammation Ieading to chronic renal insufficiency in up to 30% affected patients. In patients with suspected lupus nephritis, renal biopsy may be used to confirm the diagnosis and determine appropriate therapy. The ISN/RPS classification of LN represents a significant advance over the 1982 WHO scheme. The treatment of lupus nephritis often consists of a period of intensive immunosuppressive therapy (induction therapy) followed by a period of less intensive maintenance therapy. The established treatment of lupus nephritis with cyclophosphamide and steroids has improved the outcome of LN but is burdened with significant adverse effects. Results of clinical studies showed that mycophenolate mofetil is equally effective with fewer toxic complications than standard therapy, but its long-term efficacy is not yet known. New therapeutic agents (biologic drugs) targeted to the pathogenetic mechanism of the disease are promissing improved efficacy with less toxicity. Despite recent advances, treatment of lupus nephritis remains a challenging clinical problem.