The urinary excretion of LH, low polar oestrogens, neutral C19 and C21 steroids was measured in normal healthy males aged 20-79 years. No significant changes could be noted for the excretion of LH, pregnanediol and 17-ketogenic steroids between 50 and 79 years. The excretion of androsterone and aeticholanolone was significantly lower in the oldest group (70-79 years). A significant drop in the excretion of DHA was noted at approx. 60 years. The excretion of low polar oestrogens remained constant from 20 to 55-59 years, but showed a highly significant (P less than 0.001) decrease at about 60 years. This drop might reflect a sudden decrease in the plasma levels of oestrone sulphate due to a decreased sulphurylating activity in the liver.