Total serum IgE was measured in 119 cases of primary glomerular diseases and 33 normal healthy persons. Statistically significant higher levels were noted in minimal change disease (MCD; median: 630 U/ml), IgM nephropathy (IgMN; 618 U/ml), focal glomerulosclerosis (FGS; 373 U/ml) and membranous glomerulonephritis (MGN; 144 U/ml). A higher level of serum IgE was noted in association with more frequent relapse or steroid resistance in MCD and IgMN and in FGS with nephrotic syndrome. A small group of IgA nephropathy with nephrotic range proteinuria was also noted to have extraordinarily high serum IgE. These findings suggest that IgE may play an important role in the pathogenesis of MCD, IgMN, and FGS and may serve as a prognostic indicator in terms of steroid responsiveness in MCD and IgMN.