As newer treatment modalities become available for patients with severe lupus nephritis, it becomes increasingly important to identify patients at risk for renal failure. In this study, the records of 90 children presenting with systemic lupus erythematosus over a 13-year period were reviewed. Nineteen were lost to follow-up prior to completion of the study. Of the 71 remaining children, 16 (22%) progressed to chronic renal failure. Persistent hypertension lasting greater than 4 months, anemia, abnormalities of the urinalysis, and elevated serum creatinine level were significantly associated with progression to renal failure. Sex, race, age, abnormalities of creatinine clearance, and 24-hour urine protein collection were not associated with progression to renal failure. Renal biopsies were obtained in 45 children. Biopsies were initially classified according to World Health Organization criteria. Diffuse proliferative glomerulonephritis was significantly associated with progression to renal failure. The 45 biopsies available were reviewed by one of the authors and categorized by activity and chronicity indices. Both the active lesions of fibrinoid necrosis, synechiae, tubular casts, and vasculitic lesions and the chronic lesion of glomerular sclerosis correlated with progression to renal failure. Of the 16 children who progressed to renal failure, 2 had cadaver kidney transplants and are well 5 years posttransplant; 4 had fulminant lupus and died within 1 month of commencing dialysis; 10 began chronic dialysis. Five of the 10 children on chronic dialysis died from sepsis. These data suggest that children with systemic lupus erythematosus who undergo dialysis do poorly.(ABSTRACT TRUNCATED AT 250 WORDS)