OBJECTIVE Men with rheumatoid arthritis (RA) have a higher than normal frequency of low testosterone levels, but not much is known about other sex hormones. We investigated serum levels of estradiol, estrone, and the adrenal androgen dehydroepiandrosterone (DHEAS) in men with RA and evaluated the association of various disease variables with these sex hormones. METHODS Inflammatory activity, measured as disease activity score including 28 joints (Disease Activity Score 28), and degree of disability, measured with the Health Assessment Questionnaire, were estimated in 101 men with RA. Presence of erosions, rheumatoid factor (RF), smoking habits, and body mass index were recorded. DHEAS (not measured in patients taking glucocorticoids), estradiol, and estrone were measured in patients and in healthy controls. RESULTS DHEAS and estrone concentrations were lower and estradiol was higher in patients compared with healthy controls. DHEAS differed between RF positive and RF negative patients. Estrone did not correlate with any disease variable, whereas estradiol correlated strongly and positively with all measured indices of inflammation. CONCLUSIONS Men with RA had aberrations in all sex hormones analyzed, although only estradiol consistently correlated with inflammation. The high levels of estradiol may have positive implications for bone health. The low levels of estrone and DHEAS may depend on a shift in the adrenal steroidogenesis towards the glucocorticoid pathway, whereas increased conversion of estrone to estradiol seemed to be the cause of the high estradiol levels.