Objective: The purpose of the study was to determine whether maternal serum levels of androgens, especially testosterone, are higher in patients with preeclampsia than in matched normotensive control subjects. Study Design: Serum testosterone, dehydroepiandrosterone sulfate, sex hormone binding globulin, and estradiol levels were measured in 16 subjects in the third trimester of pregnancy with documented preeclampsia and 26 healthy, normotensive women with similar maternal and gestational ages. All subjects were primigravid women with singleton pregnancies who were seen in the labor and delivery department at North Oakland Medical Centers in Pontiac, Mich. Results: Total testosterone and free testosterone levels were significantly higher in patients with preeclampsia (213.6 ± 25.9 ng/dL and 0.5 ± 0.1 ng/dL, respectively) than in the control group (154.5 ± 14.8 ng/dL and 0.3 ± 0.03 ng/dL, respectively). There were no significant differences in sex hormone binding globulin, dehydroepiandrosterone sulfate, and estradiol concentrations. There were also no significant differences in maternal age, gestational age, body mass index, and neonatal sex. Conclusion: Levels of the potent androgen testosterone were significantly higher in primigravid women with preeclampsia than in normotensive women with similar gestational and maternal ages. This difference may indicate a role for testosterone in the pathogenesis of preeclampsia. (Am J Obstet Gynecol 1999;180:60-3.)