Lupus nephritis is a prototype of immune complex-mediated glomerulonephritis. A broad range of clinical presentations and histological changes (proliferative, membranous, or both) are observed. Patients are at risk for progressive renal function deterioration as a result of the interaction of various active immunologic and chronic sclerosing mechanisms of kidney injury. Hypertension and hyperlipidemia contribute to morbidity and mortality. Monitoring serological parameters, urinary protein excretion rate and, especially, the urinary sediment facilitate the prompt recognition and treatment of this disorder. Kidney biopsy evaluation often clarifies the type, severity, and potential reversibility of the underlying renal lesions. Although contemporary immunosuppressive regimens for proliferative lupus nephritis have reduced the risk of end-stage renal failure, they are potentially toxic and not universally effective. Decisions regarding the intensity and duration of these treatments are difficult and are based on the severity of the disease, the initial response to therapy, and the risk for drug-induced toxicities. Studies are in progress to evaluate alternative regimens for proliferative lupus nephritis and membranous lupus nephropathy.