This study sought a possible relationship between pre-eclampsia and thyroid profile. In a case-control setting, total thyroxine (T4), total tri-iodothyronine (T3), free T4, free T3, thyroxine binding globulin (TBG) and thyrotropin (TSH) levels in 39 pre-eclamptic patients were measured and compared with the levels in 42 healthy controls. We examined possible variations with regard to the severity of pre-eclampsia by dividing cases into mild (n = 17) and severe (n = 22) subgroups. Patients with mild pre-eclampsia showed significantly increased free T4 and TSH levels compared to healthy controls. In severe cases, TSH level was higher, but free T3 and free T4 levels were significantly lower than in controls. Other tests returned non-significant differences between the groups. Our findings suggest that primary hypofunctioning of the thyroid can accompany mild pre-eclampsia and possibly contribute to the pathogenesis. Elevated levels of free thyroid hormones in severe cases, however, may have reflected a preceding thyroid disorder.