Preeclampsia is an important cause of maternal and prenatal morbidity and mortality in the developing countries. Changes in thyroid function/antibodies profiles in preeclamptic women are controversial and were never investigated before in Sudan. A case–control study was conducted at Medani Hospital, Sudan, to investigate thyroid function/antibodies in preeclampsia. The sociodemographic, medical history was gathered using questionnaires. Thyroid hormones [thyroid-stimulating hormone (TSH), free tri-iodothyronine (T3), and free thyroxine (T4)] and anti-thyroid peroxidase (anti-TPO) and anti-thyroglobulin (anti-TG) antibodies were measured using ELISA. The three groups [controls, mild, and severe preeclampsia (SP) (55 women in each arm)] were matched in age and parity. While median (interquartile range) of TSH was significantly lower, both free T3 and free T4 levels were significantly higher in women with preeclampsia than in the healthy controls. There was no significant difference in the TSH levels in women with MP and SP. In comparison with women with MP, women with SP had significantly higher levels of free T3 and significantly lower levels of free T4. While anti-TPO antibodies were significantly higher, anti-TG antibodies were significantly lower in women with preeclampsia. Likewise, anti-TPO antibodies were significantly higher and anti-TG antibodies were significantly lower in women with SP than in women with MP. In linear regression, preeclampsia was significantly associated with TSH (−0.675 IU/ml, P = 0.009), free T3 (0.977 pg/ml, P < 0.001), and free T4 (0.186 ng/dl, P < 0.001) levels. In contrast to anti-TG antibodies and TSH, Sudanese patients with preeclampsia had higher levels of T3 and T4 hormones and anti-TPO antibodies irrespective of parity, gestational age, and hemoglobin levels.