Background: During normal pregnancy, changes in thyroid function are well documented; however, information regarding thyroid function in preeclampsia is scanty. Aim: The present study was planned to study thyroid hormones in mild and severe preeclamptic women and normotensive women and correlate them with outcome of pregnancy. Subject and Methods: Thyroid hormones were analyzed in mild (n = 50) and severe (n = 50) cases of preeclamptic women and normotensive women (n = 100). Results: Thyroidâstimulating hormone (TSH) and TT4 levels were higher in mild preeclampsia as compared with severe preeclampsia (P < 0.001 and P < 0.01, respectively). TT3 levels were lower in preeclampsia (more so in severe preeclamptics as compared with normotensive pregnant and nonâpregnant women). Preeclamptic with raised TSH levels had significantly higher mean arterial blood pressure and low birth weight (BW). A negative correlation was observed between BW and TSH levels (r = 0.296, P < 0.001) and BW and TT4 levels. A positive correlation was observed between BW and TT3 levels. Conclusion: These findings indicate that there is a state of biochemical hypothyroidism that correlates with severity of preeclampsia and influences obstetric outcome in these women. Identification of thyroid hormone in pregnancy might be of help in predicting occurrence of preeclampsia.