Charts of 180 patients (147 women, 33 men) with systemic lupus erythematosus (SLE) complicated by renal involvement were retrospectively analyzed from a series of 436 patients. Mean age at renal disease onset was 27 years. Thirty-six percent of the patients had renal involvement after diagnosis of lupus, for 30.7% of that group it was more than 5 years later. Renal involvement occurred more frequently in young male patients of non-French non-white origin. Patients with renal involvement suffered more commonly from malar rash, psychosis, myocarditis, pericarditis, lymphadenopathy, and hypertension. Anemia, low serum complement, and raised anti-dsDNA antibodies were more frequent. According to the 1982 World Health Organization classification, histologic examination of initial renal biopsy specimen in 158 patients showed normal kidney in 1.5% of cases, mesangial in 22%, focal proliferative in 22%, diffuse proliferative in 27%, membranous in 20%, chronic sclerosing glomerulonephritis in 1%, and other forms of nephritis in 6.5%. Distribution of initial glomerulonephritis patterns was similar whether renal involvement occurred before or after the diagnosis of lupus. Transformation from 1 histologic pattern to another was observed in more than half of the analyzable patients (those who underwent at least 2 renal biopsies). Nephritis evolved toward end-stage renal disease in 14 patients despite the combined use of steroids and cyclophosphamide in 12. Initial elevated serum creatinine levels, initial hypertension, non-French non-white origin, and proliferative lesions on the initial renal biopsy were indicators of poor renal outcome. Twenty-four patients died after a mean follow-up of 109 months from SLE diagnosis. Among our 436 patients, the 10-year survival rate was not significantly affected by the presence or absence of renal involvement at diagnosis (89% and 92%, respectively).