Cortisol and dehydroepiandrosterone (DHEA) and its sulphate (DHEAS) are the major steroid hormones produced by the human adrenal cortex. The serum levels of cortisol and DHEAS were analysed in 211 consecutive patients with renal cell carcinoma before initiation of therapy. Serum cortisol was significantly higher in patients with renal cell carcinoma compared with that in patients with benign cysts (p < 0.0001). Serum cortisol was independent of disease stage, but positively correlated to tumour diameter and grade. The serum levels of DHEAS were higher in men than in women, and decreased with age, but did not correlate with disease stage, tumour diameter or grade. The prognosis of patients with elevated serum cortisol tended to be poorer (p = 0.06) than the prognosis of those with lower levels. In a multivariate analysis, disease stage and tumour grade were independent predictors of prognosis. Age, gender and serum levels of cortisol and DHEAS were of limited value for prognosis.