IgA nephropathy (Berger's disease) is the most common primary glomerulonephritis worldwide and was once equated with benign recurrent hematuria. Longer observation showed that 15% to 30% of patients progress to end-stage renal failure after 20 years of clinical manifestations. Because the pathogenesis remains enigmatic, therapy to ameliorate disease progression can not be disease-specific. Several approaches to treatment have generated increasing interest in the last few years, including angiotensin inhibition, glucocorticoids, fish oil, cyclophosphamide, tonsillectomy and mycophenolate mofetil. For patients reaching end-stage renal failure, recurrent disease after transplantation remains a clinically important problem, despite immunosuppression since engraftment. (C) 2000 by W.B. Saunders Company.