We retrospectively evaluated the clinical and histopathological features, treatment modalities, and outcome of 53 children and adolescents with biopsy-proven lupus nephritis (LN), followed between September 1983 and September 2001. The mean age (+/-SD) at the time of diagnosis of systemic lupus erythematosus (SLE) was 12.9+/-2.6 years and the mean follow-up from the time of biopsy was 4.8+/-3.4 years. At the time of biopsy, all 53 patients had proteinuria, 21 (40%) had nephrotic syndrome, and 14 (26%) had impaired renal function. Class IV nephritis, observed in 34 (64%) patients, was the most frequent histopathology on initial renal biopsy. The patients with class IV LN had a significant tendency to develop hypertension ( P=0.04) and nephrotic syndrome ( P=0.027), and a lower mean glomerular filtration rate ( P=0.000). Based on the renal histopathology and clinical presentation, patients were treated with corticosteroids alone or combined with azathioprine or with intravenous cyclophosphamide. Plasmapheresis or cyclosporine was used in 4 and 1 patient, respectively. Follow-up biopsies, performed in 13 patients, showed no change in 6 patients, were progressive in 4, and regressive in 3. On final clinical evaluation, renal disease was in complete or partial remission in 42 of 53 patients (80%), 4 had clinically active disease but with normal renal function, and 7 (13%), all with WHO class IV LN, were classified as having an adverse outcome, i.e., either preterminal (2) or terminal (4) renal failure or death (1). Five-year kidney and patient survival rates from the time of biopsy to the endpoints of terminal renal failure or death were 88.6% and 98.1%, respectively, in the whole group, and 82.4% and 97.1%, respectively, in the WHO class IV group. Nephrotic syndrome and class IV nephritis at initial biopsy were the only parameters significantly associated with adverse outcome in our study group. There was no association with gender, age, hypertension, impaired renal function, anemia, increased morphological index scores, and treatment modalities. We conclude that clinical and histopathological features of LN and treatment regimens in our study do not differ markedly from those in most pediatric series. However, the 5-year kidney and patient survival rates are among the best reported in recent pediatric series. The prognosis of LN is primarily dependent on the histopathological lesions.