Abstract: Systemic Lupus Erythematosus (SLE) is a rather frequent disease in Iran. In the past 13 years, 449 patients with SLE attended the SLE clinic. Lupus nephritis was discovered in 278 of them. The purpose of this study is to demonstrate the caracteristics of lupus nephritis in Iran (percentage of proteinuria, hematuria, leucocyturia, casts, renal insufficiency, hypertension, and patterns of renal biopsy), to compare them to the remaining patients with SLE but without renal involvement (some manifestations were seen mor frequently in patients with lupus nephritis), and finally to compare the Iranian with Western Lupus Nephritis (the higher incidence of diffuse proliferative glomerulonephritis in Iranian patients and the low frequency of focal proliferative glomerulonephritis and membranous glomerulonephritis in Iranian patients).