Worker exposures to estrogen (57636) were surveyed at two pharmaceutical companies (SIC-2834). Company 1 produced tablets containing natural, conjugated estrogens and employed about 840 workers; 75 were involved in the manufacture of estrogenic products, and 30 of those 75 were intermittently exposed to natural conjugated estrogens. Company 2 produced oral contraceptives containing mestranol (72333) and norethindrone (68224), and employed about 1200 workers; 200 to 250 were involved in the manufacture of estrogenic products. Personal and area air samples and skin wipe samples were collected. Several workers completed medical questionnaires, and blood chemistry and estrogen values were determined. At Company 1, airborne concentrations of total conjugated estrogens ranged from 0.48 to 5.32 micrograms per cubic meter (microg/m3). At Company 2, mean concentrations of mestranol ranged from 0.052 to 1.04microg/m3. Estrogens were found on skin wipe samples. At Company 1, exposed workers had higher hematocrit values and lower antithrombin III values than unexposed workers. At Company 2, blood ethynylestradiol values increased over successive work days. The authors conclude that some exposures to estrogens exist, but exposures do not appear to be clinically significant. A full scale medical/industrial hygiene survey is not warranted, but work practices and control technologies should be evaluated.