We had a 20-year-old male patient of secondary aldosteronism similar to Bartter's syndrome, which had proved to be evident after the remission of nephrotic syndrome. In the patient, hypokalemic alkalosis and hyperreninemic hyperaldosteronemia were observed, although the blood pressure was normal. Hyperplasia of juxtaglomerular cells was observed and no abnormalities indicating either glomerulonephritis or renal artery stenosis were found; the pressor response to intravenously infused angiotensin (ang) II was markedly decreased; urinary prostaglandin (PG) E2, kallikrein and kinin excretion were elevated. The inhibition of PG synthesis with indomethacin decreased renal PG production and partially corrected both hypokalemia and pressor responsiveness to ang II. Thus, this case is considered to be a case of Bartter's syndrome. Contrary to the previously reported observations, the effective fractional chloride reabsorption rate in the renal distal tubules was normal (> 80%) and not changed by PG inhibition. Plasma atrial natriuretic peptide level was normal. An interaction between renin-angiotensin and PG systems appears to play a prior role in this case. To explain the pathophysiology, we have hypothesized an abnormal function of ang II receptor signal transduction which excessively stimulates PLA2, resulting in overproduction of PG synthesis in tissues.