A severely burned patient was admitted and resuscitated. She maintained normal blood and urine volumes, normal osmolality and renal functions. During the burn shock period, blood and urine samples were collected for measurement of ADH by means of radioimmunoassay. Marked oversecretion of ADH and cortisol was noted, independent of changes in plasma osmolality and volume, which remained stable. It was concluded that under such circumstances, stress and severe pain in burn shock may be the chief factors in producing the very high levels of ADH and cortisol in blood and urine.