Membranous nephropathy is the most common pathologic lesion in adult patients with nephrotic syndrome. The cause is idiopathic, and the pathogenesis is believed to involve the deposition of immune complexes in the subepithelial tissue of the glomerular capillaries. After a period of 5 to 10 years, one-third of patients with membranous nephropathy will develop spontaneous remission, one-third will develop sustained proteinuria, and one-third will experience progression to chronic renal disease. Proteinuria may recur in patients who are in complete remission; this has been reported in approximately 26% of patients during an average of 89 months. To date, however, recurrence of membranous nephropathy has not been reported in patients who have been in complete remission for ≥ 20 years. We report herein such a case. Membranous nephropathy may recur in adult patients who are currently in the remission stage. Ongoing follow-up is therefore required, even after several years of complete remission.