Hyperkaliema at 6 mmol/l was discovered in a 30-year old man during routine examination. Further investigations showed that the hyperkaliaemia was associated with hyperchloraemic acidosis, stimulable hyporeninaemia and relative hypoaldosteronism in relation to the hyperkaliaemia. Renal and adrenal functions were normal. The finding of 3 identical cases in a French family of 9 persons led to the diagnosis of Gordon's syndrome, a rare hereditary metabolic disorder with a controverted physiopathology.