['To determine whether patients with erectile dysfunction (ED) have a higher incidence of insulin resistance (IR) when compared with controls.', 'Prospective case-control study.', 'Academic medical center.', 'Twenty-nine nondiabetic men aged 18-66 years were enrolled. Of these, 28 completed the study: 17 had ED, and 11 did not.', 'Validated ED questionnaires, examination, serum hormones evaluation, and oral glucose tolerance testing.', 'Association of IR with ED.', 'The association between worsening degrees of both lower urinary tract symptoms (LUTS) and ED was reaffirmed, as was a potential correlation between the two-epinephrine. There was a negative association between serum levels of epinephrine and scores on the 5-item version of the International Index of Erectile Dysfunction for ED (Spearman correlation coefficient = -0.38). On the other hand, men with ED were not more likely to have IR compared with controls.'] Is epinephrine associated with both erectile dysfunction and lower urinary tract symptoms?