Objective: To compare the effects of continuous noncombined transdermal estradiol versus oral conjugated estrogen on serum sex hormone-binding globulin (SHBG) levels prior to and during the 10th and 22nd weeks of therapy in patients with surgical menopause. Study design: Open, comparative trial. Patients were consecutively assigned to three groups: group 1 (n=18) received continuous transdermal estradiol (0.050 mg/day), group 2 (n=18) continuous oral conjugated estrogens (0.625 mg/day), whereas group 3 (n=15) received no treatment. Serum SHBG levels were determined before treatment and after 10 and 22 weeks of treatment. Results: Serum SHBG increased significantly with oral conjugated estrogens at 10 (p<0.01) and 22 weeks (p<0.01) compared with baseline. With transdermal estrogens there was a much smaller increase of SHBG. At 22 weeks, this increase was significant compared with baseline (p<0.05), but not compared with the control group (p>0.05). Conclusion: Transdermal estrogen has no effect on SHBG, whereas oral conjugated estrogens causes a considerable increase. (C) 1997 Elsevier Science Ireland Ltd.