IgA nephropathy first described by Berger and Kinglais is the most common form of primary glomerulonephritis. Incidence of this disease varies in different geographical regions of the world. In Asia, it is present in 30 to 40 percent of all biopsies, 20 percent in Europe and 10 percent in North America. This wide variation in incidence may be due to genetic reasons or because of differences in indications for renal biopsy. Autopsy studies from Singapore report 2 to 4. 8 percent of the population may have IgA deposition in the glomeruli. IgA has two subclasses, IgA1 and IgA2. Approximately 90 percent of serum IgA is of the IgA1 subclass. Polymeric IgA1 is the predominant immunoglobulin found in the glomeruli of patients with IgA nephropathy. In some patients with IgA nephropathy, antibodies to dietary antigens or to various bacterial and viral agents have been detected in patients’ serum.