Only four cases of immunoglobulin E (IgE) monoclonal "gammapathies" have been reported previously. Discussed here is a 57 year old man who presented with hypertension and the nephrotic syndrome. A monoclonal IgE-kappa component (0.6 mg/ml), which did not appear as an M spike on protein electrophoresis, was demonstrated by immunoelectrophoresis in the serum and urine. The patient's condition deteriorated rapidly due to renal failure, and he died five weeks after the diagnosis was made. Pathologic examination disclosed extensive glomerular lesions, but amyloid was not detected by light or electron microscopy. The possible relationship between the monoclonal gammapathy and kidney impairment is discussed.