The sympathico-adrenergic system and the hypophyseal-adrenocortical system mediates the regulation of the internal milieu. And the kidneys regulate both water and electrolyte balance of the body fluid. The kidneys are the sites of production of renin which participate indirectly in maintaining renin. angiotensin-aldosterone system. These system de-serve special attention in the context of adjustment the effects on the body function. And so, maximal exercise and work load are associated with home-osthetic function. The nurses working in the hospital have been complained of fatigue and stress by frequent duty changes and overload. In order to define this, the possible changes of hormonal excretion during three-shift nursing practice were investigated. Urine samples were collected at pre-duty and post-duty, and were measured with chemical assay and radioimmunoassay in 30 nursing students, in nursing practice and 43 nursing students, in studying. The results obtained were as follows. 1. In nursing practice, urinary norepinephrine concentration showed a marked increase during day duty, urinary cortisol concentration showed a marked increase during evening duty, and urinary renin concentration was increased in night duty, 2. Corrected ratio of urinary sodium excreted by the urinary excretion of creatinin (UNa/UCr) and UCl/UCr showed a marked decrease during night duty. Nursing practice did not affect on the UK/UCr and urinary concentrating ability. From these results, it is suggested that further studies the define the effects on some physiological function of the three-shift nursing practice against circadian rhythm are needed for better working condition of nurses.