Dialysate contents of 17-hydroxycorticosteroids (17-OHCS) in hemodialysis patients were studied as a potential measure of adrenocortical function. Dialysate 17-OHCS contents after a 2-day interval of hemodialysis in 15 hemodialysis patients were determined. Dialysate 17-OHCS increased after intravenous injection of cortisol the evening prior to hemodialysis (n = 4). Dialysate 17-OHCS content was suppressed, as was plasma cortisol, after a standard dexamethasone (Dex) suppression test (n = 1). Their plasma cortisol was suppressible or nonsuppressible by an overnight Dex suppression test, as reported previously. However, basal dialysate 17-OHCS contents were not different between them, indicating that the nonsuppressible patients with overnight Dex seem not to have hypercortisolism. We conclude that determination of dialysate 17-OHCS seems a useful noninvasive technique for the evaluation of adrenocortical function in hemodialysis patients.