We assessed the association between cigarette smoking and basal levels of adrenal cortical hormones in 11 postmenopausal smokers and 11 postmenopausal nonsmokers and measured the acute adrenal effects of cigarettes in the smokers. After an overnight food, alcohol and tobacco fast, participants smoked or sham-smoked every hr for 8 hr and provided serum samples for hormone assay before and after every other cigarette/sham, as well as before and after a corticotropin stimulation test. The postmenopausal smokers had substantially higher basal levels of androstenedione (4.60 +/- 0.42 vs. 2.70 +/- 0.36 nmol/l, P < .05) and dihydroepiandrosterone sulfate (2.88 +/- 0.36 vs. 1.91 +/- 0.16 mumol/l, P < .05) and higher average levels of cortisol and androstenedione from 0800 to 1300 hr (351.0 +/- 17.5 vs. 295.5 +/- 17.1, nmol/l and 3.58 +/- 0.42 vs. 2.51 +/- 0.19 nmol/l, P = .03, and P < .05, respectively). There were small acute effects of individual cigarettes on the hormones, but the response to corticotropin was similar in smokers and nonsmokers. Our results indicate that cigarette smoking causes a generalized disturbance in adrenal cortical hormone levels. There is no evidence for acute tolerance to the adrenocortical affects of the hourly smoking of medium-nicotine cigarettes, but these acute effects do not explain the higher hormone levels in smokers. There is no evidence for a partial block in the cortisol synthesis pathway to explain the increased adrenal androgen levels in smokers.