Epidemiological and immunological evidence has suggested that female sex hormones may play a role in the etiology and course of autoimmune diseases such as rheumatoid arthritis (RA). In this review the present clinical data with regard to estrogens and RA are discussed, with emphasis on the possible preventive effect of oral contraceptives on the incidence of RA and on the possibility of using estrogens as adjuvant therapy in RA. It is concluded that oral contraceptives may mitigate or postpone the onset of RA slightly, but that estrogens are not able to alleviate the symptoms of RA. Presently there is no evidence to promote the use of estrogens in preventing or treating RA in females.