**Abstract**

Systemic lupus erythematosus is a chronic autoimmune disease that affects mostly women. The kidneys are involved in 50% of patients causing a high degree of disease morbidity and mortality with poor prognosis. Early diagnosis of lupus nephritis with prompt therapy correlates with a better outcome. The renal biopsy provides important informations to clinicians to monitor the patients. The patterns of glomerular lesion, degree of activity and chronicity of the disease and extent of lesions to the tubulointerstitial and vascular compartments are fundamental information for the clinician to decide the most appropriate treatment. In order to correlate the kidney disease with clinical manifestations and patient outcome the glomerular lesions are classified according to International Society of Nephrology and Renal Pathology Society Classification (ISN/RPS). The definition of active and chronic lesions was introduced by studies conducted at National Institute of Health (NIH). The ISN/RPS classification and NIH indices have recently been revised by a series of retrospective validation studies to improve and minimize the controversial aspects.

**Keywords:** Systemic lupus erithematosus, lupus nephritis, renal biopsy, ISN/RPS classification, NIH activity and chronicity indices, patients management, prognosis
