Urinary levels of steroid metabolites (17-hydroxycorticosteroids and 17-oxosteroids) were measured in 408 males at two times during the normal working day. Hormone levels are expressed both as rates of excretion and as creatinine ratios and are compared with the values for adrenaline and noradrenaline previously measured in the same samples. Strong associations are found between catecholamines and steroids. Generally the greatest correlation is with hormones of the same biochemical class, although the 17-hydroxycorticosteroid level is more strongly correlated with the adrenaline level than is the level of noradrenaline.