This case report describes a patient with essential hypertension in whom captopril during seven months resulted in a nephrotic syndrome. A renal biopsy specimen revealed membranous glomerulopathy stage I. After withdrawal of the drug, urinary protein loss disappeared within ten days. However, a second biopsy three months later still showed granular deposition of IgA, IgG, IgM and C3 in the glomerular basement membrane and unchanged subepithelial electron-dense deposits on electron microscopy. Glomerular filtration rate remained normal during the observation period.