Investigators in 13 pediatric nephrology centers reviewed clinical and pathological features in 218 children and adolescents with IgA nephropathy (IgAN), with particular emphasis on 80 patients who had follow-up periods of at least 4 years. Potential prognostic markers in the 80 children were compared between 12 (15%) who developed end-stage renal disease (ESRD) versus 68 who did not. The relationship between clinical and pathological features and the subsequent development of ESRD was examined using stepwise linear discriminant analysis in addition to standard univariate analysis. Seven variables were found to be predictive of ESRD: the presence of glomerular sclerotic changes, especially when this was associated with proliferation or sclerosis in 20% or more of the glomeruli; black race; hypertension at biopsy; proteinuria at biopsy; age at presentation; crescents; male sex. Using the resulting discriminant function, development of ESRD could be correctly predicted in 95% of the subjects. We conclude that ESRD is more common in American children with IgAN than was realized previously. Risk factors previously documented in adult studies have been confirmed, especially the presence of glomerular sclerosis, proteinuria, and hypertension.